Under the guise of a steaming shower, a curious sister spies on her stepbrother, watching him stroke his massive cock to porn. Turned on, she decides to join, slipping in behind him, her soapy hands exploring his body. He's rock hard, and she can't help but press her tits against his back, grinding her wet pussy on his ass. He spins around, hungry for more, and soon, he's fucking her tight ass, their bodies slick with soap and water, the shower echoing with their moans and the sound of their bodies colliding.