hey man good luck on that...cuz i got that same prob. but i did cum once and that was because the one girl had a vibrating tongue ring...and man that feels good as shit
Just finish yourself off over her and then massage your sperm into her skin afterwards, include her in your orgasm like that (after all, the chances if her getting your precise rhythm going is pretty slim),lots of women find that extremely sexy, and it's great for the complexion!