Despite what Internet memes may describe, this is not horror beyond the stars ready to devour your brain. And we know it's not because it involves fictional underage people that those memes are created, because I don't see memes of such intensity about lolicon.
Boku no Pico is part of a sub-genre of porn known as "trap". Let me explain: "we draw a girl, voice like it a girl if our work has voice, and then make the character a male". Who the hell does these appeals to, you ask? Good question, but it is certainly falling more on the straight male/lesbian side of the equation than standard gay porn.
Pornography is an extremely subjective topic. If it doesn't tingle your senses in a positive way, it's like speaking alien language. Or, you know, horrify or disgust the hell out of you. Many people commit the error of watching certain kinds of pornography and then saying, "that aspect ruined the work for me". Milady, please, it was never meant for you. It's like watching a slow drama of a girl afflicted with cancer and expecting car chases and explosions.
Let me talk about the aspects that aren't fetish-specific: this series is well-animated and drawn. One may say, it's even high-refined. Saigado, who is an artist most well-known for doujinshis of The King of Fighters in the West, put all his effort in drawing skinny and the same time curvy bodies here. Despite looking feminine, they still look sufficiently masculine and don't delve into the uncanny valley, if a little stylized. The animators also make good of their budget and the animation comes off as fluid and natural as can be for a hentai OVA, who aren't exactly high budget anyway.
The story is basically an excuse for porn and with such a short runtime it even couldn't not be. It makes up for it with well-animated scenes. The voice-acting is also very professional.
But look, for the love of God, stay away from this if you're not into the trap genre. It will only horrify and disturb you. And remember: a bunch of twenty-year old women voiced those drawn boys. No minors were harmed. Just like those three billion of people in the last disaster movie you saw. I'm more afraid of Trey Parker putting his daughter Betty to say swear words on South Park.