My girlfriend's sister always seduces me and I can't help myself

Akari Neo is a beautiful older sister who goes to her sister's house every day to play, but one day she accidentally saw her sister having sex with her brother-in-law, which made her heart sob. After that, she masturbated at home and did nothing else, until one time at a party and her brother-in-law was drunk and she came over to make love to him and let him feel her vagina contract.