This is so sexy. My wife and I have tried this a few times, but her breasts are too big and my cock is too small for her to be able to tit-fuck me while sucking my dick. The minute she tries to squeeze my tiny cock between her breasts, it's so small that it just disappears completely and she can't suck it. For her to be able to suck my dick at all, her breasts have to be totally out of the way.
But - I guess having a wife whose breasts are way too big for your cock is a good problem to have...