The original Papakiki manga is very much moe driven, though it seems the author can scarcely resist his pervy urges as there are constant fanservice shots. They are usually tasteful, though nipples do appear a small number of times. One of his many spinoff manga efforts is far less reserved. It is a must read.
The Rojou Kansatsu Kenkyuu Nisshi spinoff is almost porn, it has a ton of nudity and highly sexual situations, while maintaining the feel of an ecchi manga, rather than a hentai.
Unfortunately, the anime spinoff would take a very different tact, offering no nudity despite being animated by feel, a company that has been willing to go pretty far when it chooses to.
The Rojou Kansatsu Kenkyuu Nisshi spinoff was reader submitted.
Papa no Iukoto o Kikinasai! manga (3 volumes, complete)
Papa no Iukoto o Kikinasai! – Rojou Kansatsu Kenkyuu Nisshi manga (31 chapters, ongoing)
The only shame is that for the life of me I can’t find anyone other than Japanzai who’s scanned this awesome spinoff version, and some jackass at Japanzai put watermarks right on the T and A at times. I have nothing against watermarking (even though it’s a tad dubious considering that they don’t actually own the material and are pirating it just like everyone else), but if you are the only source releasing certain content, I think there’s kind of an unwritten rule that you don’t abuse that power and ruin the fun for everyone else.
That’s just what I think anyway (which isn’t worth much). And though it irks me, I’ll never badmouth someone who goes through all the trouble of scanning and translating, especially when the were the only ones to do so, apparently. A couple of “jokes on us” gags are a small price to pay.