The act of shoving an axle handle up your sphincter while masturbating in an alien costume.
Chris and Brett are home taking turns doing Paul Bunyon"s on each other while Jeff is filming.
Two dicks in one hole thus the shafts of each penis would have to touch. The gyrating motion of sex would cause each shaft to slide past the other. This issue can happen on purpose or accident.
Micah and Tim were banging Cindy one in the pink and one in the stink when Micah slid out and instantly joined Tim in a sliding trombone