A blonde pre-adolescent boy who works part-time at his grandfather's bar in the summer. He's often shown swimming, usually naked or in a blue speedo. He wears girls' clothing after when Mokkun suggests it. Later, hurt that Tamotsu wouldn't define their relationship, he rebels by cutting off most of his hair and runs away.  The following summer, he spots Chico swimming nude in a stream while cycling. He soon befriends the other boy, who calls him "oniichan" and forms a sexual relationship with him. In his relationships with both Mokkun and Chico, he is the uke, though the latter is somewhat reversible.  (Source: Wikipedia)

Pico and Mokkun enjoy a nice date at the amusement park, but Mokkun has ulterior motives.


The third installment of the Boku no Pico series, which takes sometime after the second OVA, Pico to Chico. 
Pico and Chico meet a mysterious young boy named CoCo, whom Pico at first believes is a girl. The three of them become friends, but soon CoCo believes he is becoming a strain on Pico and Chico's relationship and decides to distance himself from them. The three of them rekindle their friendship by the end of the OVA.

The crisp rays of summer sun find the effeminate Pico embroiled in yet another heated and lustful fling. While out biking, Pico meets and befriends Chico—a lively boy not much younger than him, but leagues behind in the affairs of the flesh. After the innocent Chico shows his sister in the midst of self-pleasure to Pico, Pico takes it upon himself to educate this confused youth. 
 
(Source: MAL Rewrite)

During summer vacation, Tamotsu is on break from work happens to visit a particular café. It is at this café that Tamotsu meets Pico, who works there for his grandfather. Tamotsu instantly falls for Pico, believing that Pico is a girl because of his feminine appearance. However, to his disbelief, Pico claims he actually is a guy. Undeterred, Tamotsu pursues a sexual relationship with Pico, to an extent where he even persuades Pico into wearing girl clothes. When Pico asks what is he to Tamotsu, he finds himself unable to answer... 
(Source: MAL Rewrite)