Japanese anime porn.
If a anime character exposed his/her sex organs(sexposed), having sex, using sex toys, they will be a hentai.
Hentai are drawn unofficially by fans not by anime company.
Some people jack off with hentai, some said that sicks, and I and some people laugh at their huge boner. I edited Ash's boner on a hentai image to a rocket.
One of a funny hentai picture is Ash and Brock licking Misty's vagina. They had a huge boner so I colored that boner into rainbow color! LOL