First, don't just add sex for the sake of sex. It really shouldn't just come out of left field for shock value or "maturity" value.
Second, less is more. Of all the "love" sceens i've seen in games so far, they all seem to be awkward, clunky, and inpassionite. Graphics are great now a days, but still they lack, for the most part, facial detail, emontional inflection and body language, all of which is importent. So, don't bother wtih it. Set the sceen with dialog and basic actions then fade to black or pan away and let it be implied. If you look at ME 2, for example, the sceens with Moranda and Jack are awkard and clunky, and unrealistic. The stuff with Tali, where, it's 90% dialog and then they pan away.. it works MUCH better IMO. Stuff like that.
Second, less is more. Of all the "love" sceens i've seen in games so far, they all seem to be awkward, clunky, and inpassionite. Graphics are great now a days, but still they lack, for the most part, facial detail, emontional inflection and body language, all of which is importent. So, don't bother wtih it. Set the sceen with dialog and basic actions then fade to black or pan away and let it be implied. If you look at ME 2, for example, the sceens with Moranda and Jack are awkard and clunky, and unrealistic. The stuff with Tali, where, it's 90% dialog and then they pan away.. it works MUCH better IMO. Stuff like that.