LF Doujinshi - Boy with octopus tentacles from back, milf scientist, shower scene

Hello everyone!

I'm looking for a hentai doujinshi/manga I read around last year, but I forgot the title. It was full color and had really nice art.

What I remember:

• The protagonist is a boy who looks mostly human, but he has octopus-like tentacles coming out from his back (maybe more, like semi-human octopus hybrid). I think he also had octopus eyes or something similar.
• There's an older woman (milf/teacher/scientist type) who seems to be his superior or mentor. She's more adult/mature, acts like a doctor or scientist.
• The setting is post-apocalyptic. It starts with the boy doing an underwater mission/exploration at the bottom of the sea, investigating something in the ocean depths.
• He returns to a base or facility, the woman greets him and says something like "good job on the mission" or "you did well".
• Later, the boy tries to sleep but can't, so he gets up to go to the bathroom.
• There he accidentally runs into the woman who's just coming out of the shower naked.
• He loses control, and they have a encounter right there.
• Then it turns out there's an AI or assistant that was watching/monitoring everything, and it says something like "The first phase of the repopulation plan has been completed" or similar (murmurs it to itself).
• It felt like the AI had a bigger plan involving him and her for repopulating or some experiment in this post-apo world.
• Art was full color, good quality, and I think there might be a sequel or continuation planned.
• Not sure about tags exactly, but probably includes: tentacle (from the boy), monster boy, milf, scientist, post apocalypse, shower sex, maybe sci-fi elements.

Does anyone recognize this? Maybe it's an original doujin or from a small circle. Any help finding the title, artist, nhentai code, or even the Japanese name would be awesome!

Thanks in advance!