Marc Arnaud shows his butt 2 minutes in the movie. At the same time, we also see Lionel Cecilio's butt and briefly see his penis in the background but it's off focus.
3 minutes in the movie, we see Marc Arnaud's penis in the shower as he is showering. We see him washing his penis too.
Then 4 minutes in the movie, we again see Marc Arnaud's penis in the locker room.