I've done it in bed with my GF facing away from me. This happens when she's tired and my fingering/licking her gives her an orgasm that just knocks her out. After that she's pretty much half-awake/half-asleep. I've shot it on her back a couple of times. She doesn't mind at all, she thinks it's pretty funny. She hasn't seemed to want to watch me and she won't let me watch her. I'll keep trying to convince her though!