Takayuki was dating Yuka Yuzuki, a girl who is way out of his league.
One day, Takayuki got in trouble with Kubota, an adviser to the soccer club, and Yuka steps in to defend her boyfriend. This incident pissed off Kubota so badly that he decided to revenge against Yuka, using his dick.
This happened so many times that Yuka developed an addiction and ended up disregarding her boyfriend. Much to his disgrace.