The sexual scenes involve a lot of molestation and foreplay posing, but no actual sex between anyone. And with how willing and eager both the guy and Dilein are to have sex, it's ridiculous that they never do. Not even off-camera. It also doesn't make sense that Dilein didn't bring him back to the elf world through her portal. The basic plot is that there is an elf, Silenia, and a dark elf, Dilein, who are both trying to have sex with the human boy. Silenia is annoyingly arrogant and entitled. Dilein is horny, but also pretty bland. It looks dumb how Silenia (and others sometimes) will do bowlegged squats.
Overall, this is a sexually-charge manga with annoying characters and no real plot. If its sex scenes were more hardcore, at least it'd have that going for it; but as it stands, the sexuality is just annoying.