Bob: Well it depends on how powerful the probsuction is.
Use a Henry for best results, as it gives you good eye contact, which as you is deadly sexy whilst in the act.
Can be self-inflicted.
Girl: yeah ok......pull your pants down while i plug in the hoover and get the extension pipe.
Person 2: yeah for sure, do you have the tissues?
Ten mins later...
Person 1: what did u think?
Person 2: it was so sik