Monmusu Quest!

Both consist of Monster girls in a fantasy themed world. 

If you're looking for an h-anime where a voluptuous, supernatural heroine overpowers a noticeably younger, timid male with sex, than either of these could be what you're looking for. Monmusu Quest has a greater variety of heroines, including not just succubi, but a slime, a lamia ("snake-girl") and a tentacled girl. However, it also suffers from lower quality artwork, with the most severe problems outside of sex scenes. Brandish is more comedic and has more stable art quality, but switches into a more common genre halfway through by having the heroine overpowered by a typically muscular, fully-grown man. The first half is still certainly worth seeing if that's what you're looking for. Neither attempts to actually adapt the source material. If you wanted to see the characters animated, you'll get that, but nothing more, which is the most that could reasonably be expected for a hentai work anyway. read more 

Let's give a round of applause for Monster Musume no Iru Nichijou and It's creator for making the monster girls genre more popular, since before it was almost entirely reserved for manga, I think it's safe to assume that MonMusu Quest!, A visual novel adaptation, probably wouldn't exist if it wasn't for that interest that MonMusu brought, so they're both from the monster girls genre, one is straight hentai and the other is ecchi harem, but both are enjoyable for the same reasons.