GIRL TALK: A Singing Scoundrel Is Her Best Friends BF!
I think one of my best friend’s boyfriend is flirting with me. I have music appreciation with him, and whenever we have to sing a love song, he sings it right to me, and he always sits by me, when there are like five other of his guy friends in there.
-Infinity Xs n Os,
Now, all you need to do is let him know your not interested. The easiest way to do this is completely ignore him. If he asks why he's not getting a response from you, let him know how un-cool his behavior is toward you, and that you respect your best friend's friendship enough, to not compromise it by flirting with him. He'll get the hint that his attentions are unwanted.
I hope that helps! Remember, good friends are friends till the end. Don't let some scheming stud get in the way of that.