Not literally hentai... but whatever.
Yeah I'm a big fan of the show we already have a thread on every anime of this season but I can understand how people might not see them so i'll bump them all in a bit. New ep today about 3 hours from right now.
If you keep a mal link it cause then I could help you better. Ecchi/fan service was the first genre of anime I really got into so I've seen a good bit of them some that fit your criteria here would be:
https://myanimelist.net/anime/7817/B_Gata_H_Kei (this is good but its just the first one that came to mind)
https://myanimelist.net/anime/30240/Prison_School
https://myanimelist.net/anime/268/Golden_Boy (Ova with 6 eps but comedy gold )
https://myanimelist.net/anime/19815/No_Game_No_Life
https://myanimelist.net/anime/5781/Is...shi_Monogatari
https://myanimelist.net/anime/11617/High_School_DxD (Of course the DxD series gets a mention)
https://myanimelist.net/anime/15451/High_School_DxD_New (Naturally)
https://myanimelist.net/anime/24703/High_School_DxD_BorN (Obviously this is my favorite series if you haven't noticed kek)
https://myanimelist.net/anime/5958/Sora_no_Otoshimono (3 seasons I believe I wont link em all like I did just now)
https://myanimelist.net/anime/10790/K...ka_of_the_Dead