Momoyama Hato is a brilliant mangaka, but his stories tend to be profoundly sad and disturbing, and this chapter is no exception.
Oji is a suicidal, self-loathing pederast, and Hana is a social outcast
(no small thing in Japan) who's starved for love, affection and simple
friendship. Both of them are unstable (page 19, panel 4) and all they
have is each other, as sad as that is.
Those were some professional positions he used on a virgin. Also like some cases of grooming, love persists after jail time. I'm looking at you, teachers that marry students.