Prison School!
It was just a random sketch practice but then I decided to colour it :)

Even with its shameless ecchiness, this manga is hilarious that all the ecchi is just like normal occurrence in there. It's like some drunk person in his underwear walking on a tightrope in swaying above the territories of Ecchi and Hentai but only falling down on the Ecchi side. lol
ehhh.... I wouldn't recommend this manga to younger ones and those who don't enjoy ecchi humour though pff

Prison School belongs to Hiramoto Akira