At least it is, according to his good friend James Franco's paint brush. That's not a euphemism. (Or is it?)

This is the latest chapter in Franco and Rogen's ongoing yes-homo art project.

Update: This probably isn't what Seth Rogen's penis looks like at all. I received a Twitter tip pointing to the apparent source material for Franco's paintings, these drawings by artist and Pinups magazine editor Christopher Schulz. They were released in the book Seth in 2011.