It's wrong to masturbate to your family members.
Chad's parents are out for the evening and left him and his sister alone.
Chad wants to gratify his sexual needs.
Chad closes and locks his door and gratifies himself to an erotic film on his laptop computer.
When his sister goes to take a shower, Chad spies through the door crack and masturbates to orgasm.
Chad and his sister watch a funny movie in the living-room and have a good time until their parents come home.
Chad's sister catches him peeping and their relationship becomes awkward from that day forward.