My favorite track and field club girlfriend, a slender woman with long hair, has her erogenous zones developed by the worst, most trashy senior, becoming a human masturbation aid. (Nagino Suzu FSDSS-777)

I've always been a fast runner, and thanks to the track and field club's recommendation, I was promoted to a higher level in the club and was highly regarded. Recently, I started dating Rin, a girl from the same track and field club, and everything was going smoothly… However, I don't know if I'm not attractive enough, but a senior student has his eye on me and I've been subjected to his teasing. Because the teasing was so intense, I was forced to agree to a devilish deal proposed by him, and as a result, I lost Rin, the most important person to me…