I'm guessing bc "hentai" is only "pervet/weirdo/weird person", "ero" or "ero anime" is used for that in Japan, although I'm almost certain if you walk into a shop that sells it, and refer to it as "hentai" they'll know what you mean.
Assuming you mean a sex shop, 'hentai' would refer to basically the entire store's stock, so I think you'd need to be a bit more specific! It doesn't automatically refer to manga or anime like it does in the West.
Can you expand on this? Why not?