I'm perfectly fine with ME1 scenes - those were staged well and angles did not show you any "forbidden" parts. But..you need to work at those, you know. ME1 had only 3 of them, if you remember it well, and 2 of them were actually same (mshep+Ash and femShep+Alenko).
DAO was....not bad for a fantasy dysney toon. But romantic (not to mention erotic)?..Nope. Those leather bras and pants and overall animation...well, it was not good, actually. I'm not talking about any extra mods here.
Some of ME2 were also staged nice, though aliens could not have anythng but "fade to black" (due to plain engine restriction - there is no such thing as "naked Garrus" model.
ME3 was ridiculous. Because - underwear, mentioned many times and UGLIEST arms, hands and male chest models. You got angles, you got blankets - but it's easyer to use underwear, yeah..
DA2 did not even try naked scenes. Which is, probably, for good. No ugly model animations, no seeing Default Human Male body model for Anders. They'd hardly show me anything I can't imagine myself (and probably my version of events would still be better).
I'm more concerned about emotional and sensual part, to be honest. Because most of ME3 scenes were like "oh we'll die - let's bang, ok?". ME1 and DA2 had a hint of something deeper.
If written and staged properly - the only motion of a hand may affect you more than all the naked-butt-and-boobs Liara scenes. Damn it, remember ME1 "almost kiss" locker scene! That was one of the hottest moments all over series! Remember ME1 sex scene intro - where you see companion standing REALLY CLOSE... That's what i'd love to see - not more "realism". Impressionism is a rigth word to use, I guess. Impress us, BW.
And those who need more "real" stuff - go switch TV to a special channel, or browse some sites. Videogames are not supposed to be dating porn-sim.