Is it safe to pour cement into bum?

My boyfriend has asked me to get a funnel and put it in there and pour cement and sand into his bum so he can push it out. He is very insistent that it will be fine and he wont stop asking me to do it so i'm at the point i'm just going to do it to shut him up unless someone gives me very good reason not too because i'm so sick of listening to it at the movies or at a Christmas party anywhere he says "we should go home and you can put cement in my bum." Should I do it? (wont it harden and get stuck?)