My Roommate

My roommate in college has a bbc that really stands out. It clearly shows thru his pants and he lets it hang freely when we are in the room. I sleep under him and he frequently has girls over to fuck without knowing that im there. I find it extremely hot to hear them moaning knowing that he is drilling them with at least 10" of big black dick. I want to know how i could go about asking him to clean them up when he is done? I dont know if this would be considering cuckolding but i really want to clean his sluts up after he shoots his load inside them. Any ideas on how i could ask him? Ive been thinking about this for a while and really wanna take action.