Gosh, I loved that game = D
Not only are all the aliens adorable but the whole game conveys the idea of "alien" with the lack of genitalia or anything that would be actually considered NFSW. The way that the whole process of discovering what to do to those creatures works like a puzzle that contributes to this friendly alien atmosphere and the pressing segments afterward ccontributes to change the pacing.
Sex with Aliens may not be as horny as other games about touching people and bringing them to an orgasm, but it's way more fun to play than any other game of this genre. ; )
(my only complaint with the game would be the repetitive sounds, but they're not annoying to be a problem and they're kinda cute :3 )