[GasTanker] Testing new medicine (Onii-chan wa Oshimai!) [English] is a hentai manga (doujinshi) listed in the Top Hentai catalogue. Genres include: Farting, Full Color. Featuring characters: Mihari Oyama. Part of the Onii-Chan Wa Oshimai series. Browse related titles by the same artists, genres and characters below.