I love it when my wife and I are doing some slow deep grinds, kissing passionately and she tells me to fuck her hard. I start pounding into her and she yells, "HARDER"! I then brace my feet up against the headboard, grab the back of her shoulders and go all the way from the tip of my cock down to the base and start slamming down full length, stem to stern. Nice long deep hard strokes.
Then she yells, "FUCK! Not that hard!"... Brings a smile to my face everytime.
One tip to the hard fuckers... your woman will cum hard, and when she does, tell her not to close her eyes. She needs to keep looking at you as she cums. If she closes her eyes, cup the front of her throat and order her to look at you. The intensity of the orgasm coupled with the visual cue of looking at you anchors your face to her orgasms.
You literally get hard-wired into her orgasms from then on.