The girl overheard her busty sister having sex with her boyfriend and tries to connect.

Going about her business in her room, the girl begins to pay attention to sounds like moans during sex from her sister's room. Just to make sure that everything is in order, although perhaps feeling very drunk, the sister goes to spy on what is happening there and watches as her sister's boyfriend's cock actively penetrates the latter's cunt. The sister, of course, could not resist to feel this good cock in the same way.