Wet And Juicy

You're hanging out at your girlfriends house, but she's popped out and as you walk past the bathroom, you can see her cheeky sister undressing and hopping into the shower. You find yourself perving through the door as she begins to wash herself. She catches you, but you don't seem to be going anywhere. Dolly can see how horny you are, so you might as well get your COCK out and wank for your girlfriend's sister!