If the teen boy is skinny, if it is "doing my friends mom" "my friend's mom is drunk" and so on, I don't bother listing the sites. These sites play on extremes, and don't make it clear that all participants are of age. Most often, they are part of certain organizations that I would prefer not to send clients to.
If you wouldn't make the site, if you would do free sites for it, then why would you make a listing for it?
Choose wisely, grasshopper!
Alex