For god sake, if you hate shota and naughty sex scene, just ignore it in order to save your purity. And if you haven't watched the previous 2 OVA do no try to watch this without any preparation (might be shocked during unacceptable *oops*unexpected things).
From the very start, I guess, it doesn't have a bold plot/storyline instead of how Pico found a new sex partner to allow him doing threesome (You can notice it from the title, right?). There was no such of sweet, sad -- or perhaps bitter moments, everything looks too smooth and can be handled only by sex. Let me say, for this kind of anime, story isn't that important, sex is the most ; don't you think so?
Kids and are all look like girls (cross-dressing as well), seiyuu are all girls (I guess) so it'll decrease your imagination a little for unable to think that they are completely boys, though their things were strengthening the facts they are really boys.
The details were all too great in every piece (Shape, hair, expressions, and all), modelling and costumes designs also made so sexy ; all you can do is hold your breath to watch kids wearing short shirts and revealing their navels (would boys do that ? I wonder).
Sounds and Theme Song
No doubt, they even were putting too much concerned toward the squishing, shaking, and splurting voice. The seiyuu as well can bring every kind of act into sound as it was real.
Is it what you are looking for? I guess, if you're that much hate shota but still want to see this erotic parts, so try it by ignoring them as kids (rejecting the fact and imagine as they are adults : it works somehow), may be difficult at first but you shouldn't miss the threesome scene ; it was the climax compared to the previous acts (even from previous OVA).
Afterall, no need to say, it depends on your opinion, will you watch it or not, just keep it locked from real kids...