I have a `Profile` class, which extends the `User` class, and I would like to allow every `profile` to be able to bookmark other user profiles.

I've set up the following:

```
class Profile(models.Model):
     # some fields e.g. name, email
     bookmarked_profiles = models.ManyToManyField("self")

```

Now, I'm a bit confused, for example, how would I 'bookmark' new profiles for a given profile instance?

E.g. something like 

```
# add new bookmark for profile instance
p = Profile.objects.get(pk=1)
profiles_to_bookmark = Profile.objects.all()
p.bookmarked_profiles = profiles_to_bookmark

```

I would also like to know the number of bookmarked profiles e.g.

`p.bookmarked_profiles.count()`