i've done this with my wife plenty of times at her request only though as i truly do not want to hurt her. this ONLY happens after she has cum perhaps 2 or 3 times as by this time her vagina is totally relaxed and tented and can take a real pounding without any pain. i'm kinda strong physically and i do always hold back a little in fear that if i just "let go", i can really injure her.
she and i, we both love to talk dirty. when she's ready for a good pounding, she will say something along the lines of "take my pussy and make it yours" or "fuck me any way you want" or "give me all of that cock as hard as you can"... when i hear words like this, it's the green light to go to town. for me, missionary works best, so whatever position we are in, i'll throw her on her back, spread her legs, get on top, slide in, her right leg up on my left shoulder, my left arm around that leg, push myself in as deep as i can go, lean down to her face-to-face, my right arm under her left arm and cupped behind her holding her left shoulder, she would wrap her arms around me wherever... i will then grip her very tight and adjust for best angle of attack and just literally fuck the shit out of her until i blow my load or she near-passes out from another 1 or 2 big orgasms. all this time i'm going fast, hard, and as deep as possible.
it works wonders as in this state of hers, she can take all of me without any discomfort. i don't feel any resistance inside her. it's all the way in, all the way out, and slamming it all the way back in. we've talked about this many times as when i fuck her like this there is still a small part of me that is scared as fuck that i will hurt her but she has shared that it is so fucking hot to be taken so savagely and when i do it, her orgasms are really intense.
there have been a few times when i had to stop myself as i was getting too intense and gripping her too much where i could see some pain in her face but she wouldn't say anything. dunno how to explain it really well, i guess unless you've done what i'm talking about it's hard to understand. either way, we don't do this during every sex session but it does come up every so often and when it does, i take full advantage.