Qoga sounds like it's vulgar as hell. I've got a copy right here, and by now, I'm expecting something rancid.
The thing is, the most visually "vulgar" material can be found right in the youtube video posted in this very thread that has a montage of all of the girls in battle stripping animations- so yeah, bra and panties and a little boobie bounce in Saki's animation- thats the worst you get visually.
So you basically have that and some PG13 innuendo- worst offender is probably a scene where the main character must pull a magic crystal thing out of one of the heroines- during this there is a fair amount of moaning on the females part along with a lot of talk of "reaching inside me" and "go deeper" and "feel around me as far as you can reach". Also, a bit is made of some of the girls figures -one being quite "supple" and the other being flat- really if you've played anything by Nippon Ichi recently, you know what your in for.
I personally find the cultural difference of intersex relations as portrayed by Japanese and American games quite amusing, because in JRPGS while they go as far as to have cantaly clad heroines with insane measurements, and all of the lecherous innuendo in the world, Japanese games never take these relationships any further than flirting or an end-game declaration of love. Actual sex basically almost never even seems to exist, even in the horndog world of Ar Tonelico.
On the other hand, in american games, such as those made by Bioware, you can often get with half of your party, hookers, sometimes threesomes, you name it. Everythings bedroom related happens off screen of course, but its all right there front and center for you to pursue. But yet there really isn' t much complaining (save for the Fox News Crowd) because these games aren't really about all of the innuendo.