At the beginning of the movie, Sam Rockwell strips naked and jumps from a bridge in a river. As he does that, we can see his butt and his dick. He is cut. After his swim, he gets back to his truck naked and we can see him again with a full frontal. Later in the movie, he is having sex with a girl and we can see his butt. His butt looks like a peach with a thin layer of hair.
Right at the beginning of the movie, we see Ben Affleck, with its hairy chest, getting out of bed shirtless, and as he goes to the bathroom, we see Sam Rockwell in the shower. We see Sam Rockwell's through the curtain, but quite clearly, as he is heads out the shower, we see part of his penis. 21 minutes in the movie, Ben Affleck is dressed as a clown. He drops his pants, and then his boxers. He reveals a fine butt.