Please help!!! my friend keeps bleeding!

Well recently my friend has been bleeding and there seems to be no reason why such a thing such be happening and although he is in no immediate danger he would like the incidents stopped!. The bleeding is not constant and has only happened twice before and because no accidents have happened to cause it we are all baffled as to why this should happen at all!.
They always seem to come to light when he his lying down and never when he is standing up…and is NOT a result of any white fluid that comes out of his mouth!!!
If you have any answers to his problem please comment in the box below, we both thank you in advance!