despite the way the premise sounds, the porn actually makes up less than 5% of the script (game is about 10-30 hours long) with the porn being so softcore that the most explicit it gets are visible bare nipples. if you're looking for hours of steamy lesbian sex then you're going to be disappointed.

this post explains it well too (nsfw-ish image):

http://takusan-love.tumblr.com/post/128537347043/kindred-spirits-on-the-roof-a-debunk