right, this should work

kepi/trilby_api/models/follow.py

@@ -12,6 +12,7 @@ from django.db.models.constraints import UniqueConstraint
 from django.contrib.auth.models import AbstractUser
 from django.conf import settings
 import kepi.bowler_pub.crypto as crypto
+import kepi.trilby_api.signals as trilby_signals
 from kepi.bowler_pub.utils import uri_to_url
 from django.utils.timezone import now
 from django.core.exceptions import ValidationError
@@ -71,3 +72,20 @@ class Follow(models.Model):
                     self.follower,
                     self.following,
                     )
+
+    def save(self, *args, **kwargs):
+
+        newly_made = self.pk is None
+
+        super().save(*args, **kwargs)
+
+        if newly_made:
+            logger.debug("%s: sending 'followed'", self)
+            trilby_signals.followed.send(sender=self)
+
+    def delete(self, *args, **kwargs):
+
+        logger.debug("%s: sending 'unfollowed'", self)
+        kepi_signals.unfollowed.send(sender=self)
+
+        super().delete(*args, **kwargs)

kepi/trilby_api/views.py

@@ -269,7 +269,6 @@ class Follow(DoSomethingWithPerson):
 
             logger.info('  -- follow: %s', follow)
             logger.debug('    -- offer ID: %s', offer)
-            kepi_signals.followed.send(sender=follow)
 
             if the_person.auto_follow:
                 follow_back = trilby_models.Follow(
@@ -282,7 +281,6 @@ class Follow(DoSomethingWithPerson):
                     follow_back.save()
 
                 logger.info('  -- follow back: %s', follow_back)
-                kepi_signals.followed.send(sender=follow_back)
 
             return the_person
 
@@ -300,7 +298,6 @@ class Unfollow(DoSomethingWithPerson):
                 )
 
             logger.info('  -- unfollowing: %s', follow)
-            kepi_signals.unfollowed.send(sender=follow)
 
             with transaction.atomic():
                 follow.delete()