WG,
There's a certain hip action shown in this fucking. The top isn't holding his back and hips stiff, he is curling under the bottom's ass hole, using his hips to intimately and deeply fuck the bottom, Rather than just pounding away from above. Its the way I used to fuck women and the way I like to be fucked myself. It means thrusting just with the pelvis and has the advantage of keeping faces kissing close. Is there a name for this action? If not, there should be, it is so tender and loving. Pelvis fucking?