My mate came on to me, and hes a boy! HELP!?

I think you should have a discreet and direct conversation with him, clear the air so to speak. First, ask yourself if you value his friendship. I ume you do or you would find the choices that face you easier. Why don't you tell him that what he did made you feel very uncomfortable. Tell him you are not and have no interest in the type of activities he seemed to be starting. Then say to him that you do value him as a friend and wish to remain friends, that you would never wish to hurt him but that you are disappointed and confused that he acted as he did. Then pause and let him respond. You have to be honest; this is too important. Waiting and saying nothing is sending the wrong message; it merely confuses things more and prolongs discomfort for both of you. I wish you the best; this growing up thing is sure complicated, isn't it?