Here's the best explanation of self-referential associations:
http://blog.hasmanythrough.com/articles/2006/04/21/self-referential-through
Scroll down to the comments and you'll see how it translates to a "friends" situation
Here's the best explanation of self-referential associations:
http://blog.hasmanythrough.com/articles/2006/04/21/self-referential-through
Scroll down to the comments and you'll see how it translates to a "friends" situation