Peep inside.

You could just knock to see who it is, but it's been a while since you've seen either your brother or father naked. You decide not to waste this opportunity and quietly peep through the crack. You see your brother, James lathering himself up with soap. His back is to you, giving you a full frontal view of his perfectly carved arse. He slowly begins to turn, unknowingly showing you everything. He's fairly muscular, but not too toned. You glance lower, and see his willy. You blush. You've never seen one in real life before, but you're pretty sure that it's big. You start to feel a little warm.