That sure doesn't look like a penis. Note also that the girl is on the guy's lap, so unless his penis is coming out of his belly-button, it's impossible. Judging from the guy's Japanese girlyman hand on the left, I think he's wrist-deep in vagina.
I think that the artist isn't paid to make sure that you can see the entirety of the guy's body in the h-scene,and no one can tell how long the guy's dick is because it's supposed to be blocked out.
