Stepsister gets horny drawing the naked stepbrother

The stepsister needs a model for her drawing class. She has to draw a picture of a naked boy and asks her stepbrother to pose for her. The boy lies down naked on the couch and she can't stop looking at his dick. She takes off her shirt showing her tits to make the boy more comfortable. The girl gets horny and takes off her pants too. The boy can't resist spanking her and she gets horny and gives him a blow job. The guy returns the favor by eating her pussy and then fucking her on the couch until she ejaculates inside the pussy