Kuro-kun is made to take over the debts of his father and forced to pay them off by being sold into servitude as a boy maid.

An edited version of the first OVA titled pico~ Boku no Chiisana Natsu Monogatari (pico: My Little Summer Story) was released on November 11, 2007. It is a re-edited version of the animation seen in the Boku no Pico OVA set to a new script, featuring content that is more appropriate for viewers under the age of 18. 
 
(Source: nekoshota.com)

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)

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.

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)

Natural High