Not your aass then? Cos there's that weird area where the boundaries of "arse" and "aass" cross over, though nobody in England really says "ass" unless they're aping American pronunciation. I mean Scousers sit their arses on the grass, Mancunians sit their aaass on the grass, Londoners put their arse on the grarse (lol), Somerset people put their aass on the graass and Lincolnshire's just a law unto itself.
By "aass" I mean the "aa" to be like the a in cat, but longer, with a hard 'ss' sound. How English people say cat, obviously, not Americans.