When a girl is having sex with a guy doggy style, going at it really hard and fast and one of the times his penis comes out as hes putting it back in he misses the vagina and puts it in the butt!
Girl 1: so how was jimmy last night?
Girl 2: girl he was good except he was fucking medoggy style and he gave me some surprise butt sex! And now im sore cuz jimmys got a big dick
When you are caught off guard by someone who has the intention or is in the process of invading your cornchute with no prior concent or chance of warning.