diff --git a/ormar/fields/base.py b/ormar/fields/base.py
index b11a7d7..966992e 100644
--- a/ormar/fields/base.py
+++ b/ormar/fields/base.py
@@ -267,7 +267,7 @@ class BaseField(FieldInfo):
         return value
 
     @classmethod
-    def set_self_reference_flag(cls):
+    def set_self_reference_flag(cls) -> None:
         """
         Sets `self_reference` to True if field to and owner are same model.
         :return: None
@@ -301,3 +301,13 @@ class BaseField(FieldInfo):
         :return: None
         :rtype: None
         """
+
+    @classmethod
+    def get_related_name(cls) -> str:
+        """
+        Returns name to use for reverse relation.
+        It's either set as `related_name` or by default it's owner model. get_name + 's'
+        :return: name of the related_name or default related name.
+        :rtype: str
+        """
+        return ""  # pragma: no cover
diff --git a/ormar/fields/foreign_key.py b/ormar/fields/foreign_key.py
index e141e5c..e5d187d 100644
--- a/ormar/fields/foreign_key.py
+++ b/ormar/fields/foreign_key.py
@@ -167,6 +167,8 @@ def ForeignKey(  # noqa CFQ002
     """
 
     owner = kwargs.pop("owner", None)
+    self_reference = kwargs.pop("self_reference", False)
+
     if isinstance(to, ForwardRef):
         __type__ = to if not nullable else Optional[to]
         constraints: List = []
@@ -196,6 +198,7 @@ def ForeignKey(  # noqa CFQ002
         onupdate=onupdate,
         ondelete=ondelete,
         owner=owner,
+        self_reference=self_reference,
     )
 
     return type("ForeignKey", (ForeignKeyField, BaseField), namespace)
diff --git a/ormar/fields/many_to_many.py b/ormar/fields/many_to_many.py
index b9b8049..29923d0 100644
--- a/ormar/fields/many_to_many.py
+++ b/ormar/fields/many_to_many.py
@@ -1,8 +1,7 @@
 from typing import Any, ForwardRef, List, Optional, TYPE_CHECKING, Tuple, Type, Union
 
 from pydantic.typing import evaluate_forwardref
-
-import ormar
+import ormar  # noqa: I100
 from ormar.fields import BaseField
 from ormar.fields.foreign_key import ForeignKeyField
 
@@ -71,6 +70,7 @@ def ManyToMany(
     related_name = kwargs.pop("related_name", None)
     nullable = kwargs.pop("nullable", True)
     owner = kwargs.pop("owner", None)
+    self_reference = kwargs.pop("self_reference", False)
 
     if isinstance(to, ForwardRef):
         __type__ = to if not nullable else Optional[to]
@@ -96,6 +96,7 @@ def ManyToMany(
         default=None,
         server_default=None,
         owner=owner,
+        self_reference=self_reference,
     )
 
     return type("ManyToMany", (ManyToManyField, BaseField), namespace)
diff --git a/ormar/models/helpers/relations.py b/ormar/models/helpers/relations.py
index 5acbb52..70a558c 100644
--- a/ormar/models/helpers/relations.py
+++ b/ormar/models/helpers/relations.py
@@ -109,6 +109,7 @@ def register_reverse_model_fields(model_field: Type["ForeignKeyField"]) -> None:
             virtual=True,
             related_name=model_field.name,
             owner=model_field.to,
+            self_reference=model_field.self_reference,
         )
         # register foreign keys on through model
         adjust_through_many_to_many_model(model_field=model_field)
@@ -119,12 +120,11 @@ def register_reverse_model_fields(model_field: Type["ForeignKeyField"]) -> None:
             virtual=True,
             related_name=model_field.name,
             owner=model_field.to,
+            self_reference=model_field.self_reference,
         )
 
 
-def register_relation_in_alias_manager(
-    field: Type[ForeignKeyField], field_name: str
-) -> None:
+def register_relation_in_alias_manager(field: Type[ForeignKeyField]) -> None:
     """
     Registers the relation (and reverse relation) in alias manager.
     The m2m relations require registration of through model between
@@ -136,8 +136,6 @@ def register_relation_in_alias_manager(
 
     :param field: relation field
     :type field: ForeignKey or ManyToManyField class
-    :param field_name: name of the relation key
-    :type field_name: str
     """
     if issubclass(field, ManyToManyField):
         if field.has_unresolved_forward_refs():
diff --git a/ormar/models/metaclass.py b/ormar/models/metaclass.py
index 42be22c..d6dc1c5 100644
--- a/ormar/models/metaclass.py
+++ b/ormar/models/metaclass.py
@@ -587,9 +587,7 @@ class ModelMetaclass(pydantic.main.ModelMetaclass):
                 populate_meta_sqlalchemy_table_if_required(new_model.Meta)
                 expand_reverse_relationships(new_model)
                 for field_name, field in new_model.Meta.model_fields.items():
-                    register_relation_in_alias_manager(
-                        field=field, field_name=field_name
-                    )
+                    register_relation_in_alias_manager(field=field)
 
                 if new_model.Meta.pkname not in attrs["__annotations__"]:
                     field_name = new_model.Meta.pkname
diff --git a/ormar/models/mixins/prefetch_mixin.py b/ormar/models/mixins/prefetch_mixin.py
index 04a11c8..273dd01 100644
--- a/ormar/models/mixins/prefetch_mixin.py
+++ b/ormar/models/mixins/prefetch_mixin.py
@@ -1,7 +1,7 @@
 from typing import Callable, Dict, List, TYPE_CHECKING, Tuple, Type
 
 import ormar
-from ormar.fields import BaseField
+from ormar.fields.foreign_key import ForeignKeyField
 from ormar.models.mixins.relation_mixin import RelationMixin
 
 
@@ -37,10 +37,7 @@ class PrefetchQueryMixin(RelationMixin):
         :rtype: Tuple[Type[Model], str]
         """
         if reverse:
-            field_name = (
-                parent_model.Meta.model_fields[related].related_name
-                or parent_model.get_name() + "s"
-            )
+            field_name = parent_model.Meta.model_fields[related].get_related_name()
             field = target_model.Meta.model_fields[field_name]
             if issubclass(field, ormar.fields.ManyToManyField):
                 field_name = field.default_target_field_name()
@@ -79,7 +76,7 @@ class PrefetchQueryMixin(RelationMixin):
         return column.get_alias() if use_raw else column.name
 
     @classmethod
-    def get_related_field_name(cls, target_field: Type["BaseField"]) -> str:
+    def get_related_field_name(cls, target_field: Type["ForeignKeyField"]) -> str:
         """
         Returns name of the relation field that should be used in prefetch query.
         This field is later used to register relation in prefetch query,
@@ -93,7 +90,7 @@ class PrefetchQueryMixin(RelationMixin):
         if issubclass(target_field, ormar.fields.ManyToManyField):
             return cls.get_name()
         if target_field.virtual:
-            return target_field.related_name or cls.get_name() + "s"
+            return target_field.get_related_name()
         return target_field.to.Meta.pkname
 
     @classmethod
diff --git a/ormar/models/newbasemodel.py b/ormar/models/newbasemodel.py
index ed558e0..c062d7a 100644
--- a/ormar/models/newbasemodel.py
+++ b/ormar/models/newbasemodel.py
@@ -30,7 +30,7 @@ import sqlalchemy
 from pydantic import BaseModel
 
 import ormar  # noqa I100
-from ormar.exceptions import ModelError
+from ormar.exceptions import ModelError, ModelPersistenceError
 from ormar.fields import BaseField
 from ormar.fields.foreign_key import ForeignKeyField
 from ormar.models.helpers import register_relation_in_alias_manager
@@ -452,9 +452,7 @@ class NewBaseModel(pydantic.BaseModel, ModelTableProxy, metaclass=ModelMetaclass
                 field.evaluate_forward_ref(globalns=globalns, localns=localns)
                 field.set_self_reference_flag()
                 expand_reverse_relationship(model_field=field)
-                register_relation_in_alias_manager(
-                    field=field, field_name=field_name,
-                )
+                register_relation_in_alias_manager(field=field)
                 update_column_definition(model=cls, field=field)
         populate_meta_sqlalchemy_table_if_required(meta=cls.Meta)
         super().update_forward_refs(**localns)
@@ -731,9 +729,15 @@ class NewBaseModel(pydantic.BaseModel, ModelTableProxy, metaclass=ModelMetaclass
             if self.get_column_alias(k) in self.Meta.table.columns
         }
         for field in self._extract_db_related_names():
-            target_pk_name = self.Meta.model_fields[field].to.Meta.pkname
+            relation_field = self.Meta.model_fields[field]
+            target_pk_name = relation_field.to.Meta.pkname
             target_field = getattr(self, field)
             self_fields[field] = getattr(target_field, target_pk_name, None)
+            if not relation_field.nullable and not self_fields[field]:
+                raise ModelPersistenceError(
+                    f"You cannot save {relation_field.to.get_name()} "
+                    f"model without pk set!"
+                )
         return self_fields
 
     def get_relation_model_id(self, target_field: Type["BaseField"]) -> Optional[int]:
diff --git a/ormar/queryset/join.py b/ormar/queryset/join.py
index d7b2686..0991562 100644
--- a/ormar/queryset/join.py
+++ b/ormar/queryset/join.py
@@ -135,7 +135,7 @@ class SqlJoin:
                 join_parameters.model_cls.Meta.model_fields[part], ManyToManyField
             ):
                 _fields = join_parameters.model_cls.Meta.model_fields
-                new_part = _fields[part].to.get_name()
+                new_part = _fields[part].default_target_field_name()
                 self._switch_many_to_many_order_columns(part, new_part)
                 if index > 0:  # nested joins
                     fields, exclude_fields = SqlJoin.update_inclusions(
@@ -435,11 +435,9 @@ class SqlJoin:
             from_key = join_params.prev_model.get_column_alias(
                 join_params.prev_model.Meta.pkname
             )
+            breakpoint()
         elif join_params.prev_model.Meta.model_fields[part].virtual:
-            to_field = (
-                join_params.prev_model.Meta.model_fields[part].related_name
-                or join_params.prev_model.get_name() + "s"
-            )
+            to_field = join_params.prev_model.Meta.model_fields[part].get_related_name()
             to_key = model_cls.get_column_alias(to_field)
             from_key = join_params.prev_model.get_column_alias(
                 join_params.prev_model.Meta.pkname
diff --git a/ormar/queryset/prefetch_query.py b/ormar/queryset/prefetch_query.py
index e0574a4..dda3baa 100644
--- a/ormar/queryset/prefetch_query.py
+++ b/ormar/queryset/prefetch_query.py
@@ -9,10 +9,12 @@ from typing import (
     Tuple,
     Type,
     Union,
+    cast,
 )
 
 import ormar
 from ormar.fields import BaseField, ManyToManyField
+from ormar.fields.foreign_key import ForeignKeyField
 from ormar.queryset.clause import QueryClause
 from ormar.queryset.query import Query
 from ormar.queryset.utils import extract_models_to_dict_of_lists, translate_list_to_dict
@@ -314,6 +316,7 @@ class PrefetchQuery:
 
         for related in related_to_extract:
             target_field = model.Meta.model_fields[related]
+            target_field = cast(Type[ForeignKeyField], target_field)
             target_model = target_field.to.get_name()
             model_id = model.get_relation_model_id(target_field=target_field)
 
@@ -421,6 +424,7 @@ class PrefetchQuery:
         fields = target_model.get_included(fields, related)
         exclude_fields = target_model.get_excluded(exclude_fields, related)
         target_field = target_model.Meta.model_fields[related]
+        target_field = cast(Type[ForeignKeyField], target_field)
         reverse = False
         if target_field.virtual or issubclass(target_field, ManyToManyField):
             reverse = True
@@ -585,7 +589,7 @@ class PrefetchQuery:
     def _populate_rows(  # noqa: CFQ002
         self,
         rows: List,
-        target_field: Type["BaseField"],
+        target_field: Type["ForeignKeyField"],
         parent_model: Type["Model"],
         table_prefix: str,
         fields: Union[Set[Any], Dict[Any, Any], None],
diff --git a/ormar/queryset/queryset.py b/ormar/queryset/queryset.py
index 4940265..11387b5 100644
--- a/ormar/queryset/queryset.py
+++ b/ormar/queryset/queryset.py
@@ -197,7 +197,7 @@ class QuerySet:
             limit_raw_sql=self.limit_sql_raw,
         )
         exp = qry.build_select_expression()
-        # print("\n", exp.compile(compile_kwargs={"literal_binds": True}))
+        print("\n", exp.compile(compile_kwargs={"literal_binds": True}))
         return exp
 
     def filter(self, _exclude: bool = False, **kwargs: Any) -> "QuerySet":  # noqa: A003
diff --git a/ormar/relations/querysetproxy.py b/ormar/relations/querysetproxy.py
index 841071a..7003c7a 100644
--- a/ormar/relations/querysetproxy.py
+++ b/ormar/relations/querysetproxy.py
@@ -39,10 +39,9 @@ class QuerysetProxy(ormar.QuerySetProtocol):
         self._queryset: Optional["QuerySet"] = qryset
         self.type_: "RelationType" = type_
         self._owner: "Model" = self.relation.manager.owner
-        self.related_field_name = (
-            self._owner.Meta.model_fields[self.relation.field_name].related_name
-            or self._owner.get_name() + "s"
-        )
+        self.related_field_name = self._owner.Meta.model_fields[
+            self.relation.field_name
+        ].get_related_name()
         self.related_field = self.relation.to.Meta.model_fields[self.related_field_name]
         self.owner_pk_value = self._owner.pk
 
@@ -108,8 +107,8 @@ class QuerysetProxy(ormar.QuerySetProtocol):
         :type child: Model
         """
         model_cls = self.relation.through
-        owner_column = self._owner.get_name()
-        child_column = child.get_name()
+        owner_column = self.related_field.default_target_field_name()
+        child_column = self.related_field.default_source_field_name()
         kwargs = {owner_column: self._owner.pk, child_column: child.pk}
         if child.pk is None:
             raise ModelPersistenceError(
@@ -129,8 +128,8 @@ class QuerysetProxy(ormar.QuerySetProtocol):
         :type child: Model
         """
         queryset = ormar.QuerySet(model_cls=self.relation.through)
-        owner_column = self._owner.get_name()
-        child_column = child.get_name()
+        owner_column = self.related_field.default_target_field_name()
+        child_column = self.related_field.default_source_field_name()
         kwargs = {owner_column: self._owner, child_column: child}
         link_instance = await queryset.filter(**kwargs).get()  # type: ignore
         await link_instance.delete()
diff --git a/ormar/relations/relation_manager.py b/ormar/relations/relation_manager.py
index 2e2b733..511dd7b 100644
--- a/ormar/relations/relation_manager.py
+++ b/ormar/relations/relation_manager.py
@@ -164,8 +164,6 @@ class RelationsManager:
         :param name: name of the relation
         :type name: str
         """
-        relation_name = (
-            item.Meta.model_fields[name].related_name or item.get_name() + "s"
-        )
+        relation_name = item.Meta.model_fields[name].get_related_name()
         item._orm.remove(name, parent)
         parent._orm.remove(relation_name, item)
diff --git a/ormar/relations/relation_proxy.py b/ormar/relations/relation_proxy.py
index 206db7e..1012155 100644
--- a/ormar/relations/relation_proxy.py
+++ b/ormar/relations/relation_proxy.py
@@ -42,9 +42,8 @@ class RelationProxy(list):
         if self._related_field_name:
             return self._related_field_name
         owner_field = self._owner.Meta.model_fields[self.field_name]
-        self._related_field_name = (
-            owner_field.related_name or self._owner.get_name() + "s"
-        )
+        self._related_field_name = owner_field.get_related_name()
+
         return self._related_field_name
 
     def __getattribute__(self, item: str) -> Any:
diff --git a/tests/test_forward_refs.py b/tests/test_forward_refs.py
index 7a45fca..e0e5303 100644
--- a/tests/test_forward_refs.py
+++ b/tests/test_forward_refs.py
@@ -35,34 +35,34 @@ Game = ForwardRef("Game")
 Child = ForwardRef("Child")
 
 
-class ChildFriends(ormar.Model):
+class ChildFriend(ormar.Model):
     class Meta(ModelMeta):
         metadata = metadata
         database = db
 
 
-# class Child(ormar.Model):
-#     class Meta(ModelMeta):
-#         metadata = metadata
-#         database = db
-#
-#     id: int = ormar.Integer(primary_key=True)
-#     name: str = ormar.String(max_length=100)
-#     favourite_game: Game = ormar.ForeignKey(Game, related_name="liked_by")
-#     least_favourite_game: Game = ormar.ForeignKey(Game, related_name="not_liked_by")
-#     friends: List[Child] = ormar.ManyToMany(Child, through=ChildFriends)
-#
-#
-# class Game(ormar.Model):
-#     class Meta(ModelMeta):
-#         metadata = metadata
-#         database = db
-#
-#     id: int = ormar.Integer(primary_key=True)
-#     name: str = ormar.String(max_length=100)
+class Child(ormar.Model):
+    class Meta(ModelMeta):
+        metadata = metadata
+        database = db
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    favourite_game: Game = ormar.ForeignKey(Game, related_name="liked_by")
+    least_favourite_game: Game = ormar.ForeignKey(Game, related_name="not_liked_by")
+    friends = ormar.ManyToMany(Child, through=ChildFriend, related_name="also_friends")
 
 
-# Child.update_forward_refs()
+class Game(ormar.Model):
+    class Meta(ModelMeta):
+        metadata = metadata
+        database = db
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+
+
+Child.update_forward_refs()
 
 
 @pytest.fixture(autouse=True, scope="module")
@@ -125,22 +125,56 @@ async def test_self_relation():
     assert sam_check.employees[0].name == "Joe"
 
 
-# @pytest.mark.asyncio
-# async def test_other_forwardref_relation():
-#     checkers = await Game.objects.create(name="checkers")
-#     uno = await Game(name="Uno").save()
-#
-#     await Child(name="Billy", favourite_game=uno, least_favourite_game=checkers).save()
-#     await Child(name="Kate", favourite_game=checkers, least_favourite_game=uno).save()
-#
-#     billy_check = await Child.objects.select_related(
-#         ["favourite_game", "least_favourite_game"]
-#     ).get(name="Billy")
-#     assert billy_check.favourite_game == uno
-#     assert billy_check.least_favourite_game == checkers
-#
-#     uno_check = await Game.objects.select_related(["liked_by", "not_liked_by"]).get(
-#         name="Uno"
-#     )
-#     assert uno_check.liked_by[0].name == "Billy"
-#     assert uno_check.not_liked_by[0].name == "Kate"
+@pytest.mark.asyncio
+async def test_other_forwardref_relation():
+    checkers = await Game.objects.create(name="checkers")
+    uno = await Game(name="Uno").save()
+
+    await Child(name="Billy", favourite_game=uno, least_favourite_game=checkers).save()
+    await Child(name="Kate", favourite_game=checkers, least_favourite_game=uno).save()
+
+    billy_check = await Child.objects.select_related(
+        ["favourite_game", "least_favourite_game"]
+    ).get(name="Billy")
+    assert billy_check.favourite_game == uno
+    assert billy_check.least_favourite_game == checkers
+
+    uno_check = await Game.objects.select_related(["liked_by", "not_liked_by"]).get(
+        name="Uno"
+    )
+    assert uno_check.liked_by[0].name == "Billy"
+    assert uno_check.not_liked_by[0].name == "Kate"
+
+
+@pytest.mark.asyncio
+async def test_m2m_self_forwardref_relation():
+    checkers = await Game.objects.create(name="checkers")
+    uno = await Game(name="Uno").save()
+    jenga = await Game(name="Jenga").save()
+
+    billy = await Child(
+        name="Billy", favourite_game=uno, least_favourite_game=checkers
+    ).save()
+    kate = await Child(
+        name="Kate", favourite_game=checkers, least_favourite_game=uno
+    ).save()
+    steve = await Child(
+        name="Steve", favourite_game=jenga, least_favourite_game=uno
+    ).save()
+
+    await billy.friends.add(kate)
+    await billy.friends.add(steve)
+
+    await steve.friends.add(kate)
+    await steve.friends.add(billy)
+
+    billy_check = await Child.objects.select_related(
+        [
+            "friends",
+            "favourite_game",
+            "least_favourite_game",
+            "friends__favourite_game",
+            "friends__least_favourite_game",
+        ]
+    ).get(name="Billy")
+    assert len(billy_check.friends) == 2
diff --git a/tests/test_many_to_many.py b/tests/test_many_to_many.py
index 8d8b258..8b10eae 100644
--- a/tests/test_many_to_many.py
+++ b/tests/test_many_to_many.py
@@ -80,6 +80,17 @@ async def cleanup():
         await Author.objects.delete(each=True)
 
 
+@pytest.mark.asyncio
+async def test_not_saved_raises_error(cleanup):
+    async with database:
+        guido = await Author(first_name="Guido", last_name="Van Rossum").save()
+        post = await Post.objects.create(title="Hello, M2M", author=guido)
+        news = Category(name="News")
+
+        with pytest.raises(ModelPersistenceError):
+            await post.categories.add(news)
+
+
 @pytest.mark.asyncio
 async def test_assigning_related_objects(cleanup):
     async with database:
diff --git a/tests/test_saving_related.py b/tests/test_saving_related.py
index 6dd4fd2..388e290 100644
--- a/tests/test_saving_related.py
+++ b/tests/test_saving_related.py
@@ -6,6 +6,7 @@ import sqlalchemy as sa
 from sqlalchemy import create_engine
 
 import ormar
+from ormar.exceptions import ModelPersistenceError
 from tests.settings import DATABASE_URL
 
 metadata = sa.MetaData()
@@ -61,3 +62,15 @@ async def test_model_relationship():
             assert ws.id == 1
             assert ws.topic == "Topic 2"
             assert ws.category.name == "Foo"
+
+
+@pytest.mark.asyncio
+async def test_model_relationship_with_not_saved():
+    async with db:
+        async with db.transaction(force_rollback=True):
+            cat = Category(name="Foo", code=123)
+            with pytest.raises(ModelPersistenceError):
+                await Workshop(topic="Topic 1", category=cat).save()
+
+            with pytest.raises(ModelPersistenceError):
+                await Workshop.objects.create(topic="Topic 1", category=cat)