My girlfriend and I have done this a few times. Most recently a couple of days ago. She sucked and wanked me at the same time. She then took all my cum into her mouth and really squeezed and sucked to make sure she had every drop. She then gave me a mouthful of cum, then another load. There was so much in there I struggled to keep it in my mouth. Very hot.
I've done it with my wife many times (back when we were having sex). The first time was when we were having sex, she came a couple of times, and then had me pull out and she took me in her mouth (she liked her taste on my cock). This time she said to go ahead a cum in her mouth. When I was about to cum I told her not to swallow (she always did) and after I filled her mouth I pulled her up and locked my lips on hers, and then pushed my tongue in. She groaned as she let me suck my cum out of her mouth. Gawd that was hot! Wish she'd still be doing it!