1. Japanese animation, comics, pictures, or whatever, using animated characters, often having better bodies than real people, in sexual situations. Since anything can happen in a cartoon, hentai is pretty much limitless.
2. If you pedophiles over there ignore the fact that hentai is fictional characters who don't exist, it can be a good way to get child porn without being arrested.
3. Hentai characters come in ALL forms. Yes, even furries can star in a hentai comic.
1. Oh my fucking god, Kuwabara's "Spirit Sword" just went up Yukina's ass!
2. Dude, I just whacked off to Chibi-Usa
3. Watch as Sonic the Hedgehog
does it three-way with Tails and Amy!