The lucky boy is being seduced by his girlfriend's sister.

This guy has a cute young girlfriend, but she's not good at sex and his frustration is growing. That's when Meguri, my girlfriend's older sister, comes in. She is older and has more experience. Not only is she beautiful and better at sex, but she also doesn't care about using condoms. And that's the key to this story. With this free cake sex party, the guy becomes a little careless, and he risks getting caught by his real girlfriend.