It's from "Over Doser", by Ruru: https://kof-dj-index.tumblr.com/post/164028355252
Sadly, that story is just comical and don't have any porn. >>2662979
The blog I linked above scan doujins and eventually official mangas and novels. They are active and posts news, trivia and even translate some stuff from time to time:https://kof-dj-index.tumblr.com/
But because of tumblr ban they made a backup site, so for doujins with adult content they post only the cover with a link to the site so you can read it there instead of on tumblr. They have download links for everything so it's easier to save what you want. >>2663012
At this point I think only a miracle could save that site. Not only the management and porn ban is ridiculous, but the users in general are unbearable. Some years ago you could at least just follow the artists you liked in peace and ignore the discourse crowd, but things reached a point where any artist who start to get any minimal recognition will be put on a witch trial and have their entire past analyzed. If anything remotely ~problematic~ is found, then the person is accused of being a pedophile and tormented until they give up and leave. A lot of artists migrated to twitter since things are a bit better to handle there.
Just to end my rant, I remember some months ago an artist who drew Moomins fanarts and was getting popular because of the new animated series was acused of pedophilia. The motive? Someone went to their pixiv account, looked into their bookmarks and saw that one of the things they faved was a image set where one of the images had a ~problematic~ ship.