Sleeping with them together.
boyfriend's best friend.coz if he gets to know,which he will,thats the end of your relationship whereas your best friend will never get to know whether you slept with her boyfriend as he wont tell her.
Dont know because havent tried it.
Boyfriends best friend. I think that hurts more.
I was in that situation. my best friend's boy friend and my boy friend's best friend were the same person. That was alot of fun sex. He could put it down.
What if they are the same? no dilemma, except then you **** off two people, instead of one.