I became the boyfriend of Saeko, a senior at my part-time job, but she didn't want me to have sex with her because she didn't like the fact that I was a virgin. So I tried a dating app and found Saeko's older sister, Mariko! Her husband was working overseas and she was frustrated, so we started our sex friend relationship on the condition that we keep it a secret from each other... Unlike my girlfriend, Mariko even lets me cum inside her, and sex with her feels so good it melts my body and Kokoro! And my desire escalates more and more, and we start having sex secretly at home too...