is the realism involved here.they don't fall in love. He brings Pico around slowly, taking him out for ice cream, giving him blowjobs in the car, then finally bringing him around to his apartment. Mokkun, a somewhat bland character, sees Pico and ends up having sex with the underaged boy.
There is no romanticism in this OVA, which is odd, considering the content. But it's what lies beneath, what goes unsaid that makes this a somewhat disturbing OVA, more so than the following two episodes that also feature Pico.
On the surface of things, Boku No Pico is nothing more than a very well animated shota with lots of sex scenes.