Watches a movie with her stepbrother and sucks his dick

This girl lives with a teenage stepbrother who is always flirting with her and insinuating sexual desire. He is quite an attractive and intelligent boy, but the girl feels that he is too young for her and that to be with him would be to commit incest, due to how close his upbringing has been. One weekend night they both stay home and decide to watch a movie to pass the time. The movie gets a little erotic and they both get excited, so the boy takes the opportunity to grope his sister and get her to have sex with him. The girl gets excited with everything her stepbrother does to her and starts sucking his dick.