It is not but thank you for this! (≧∀≦)
oh god my brain knows this... is this the one where he's the teacher and he's harassing hiji, like hijikata was attending class with a vibrator up his ass? (though now i don't think it was a harada story)
anyway, here are some ginhiji that are student x teacher, but it's not from here
https://myreadingmanga. info/gekirin-syaku-worlds-end-call-1-gintama-dj-eng/ (has 4 chapters)
https://myreadingmanga. info/gekirin-syaku-stromatolite-gintama-dj-eng/
https://myreadingmanga. info/plug-nagisa-gintama-dj-rewrite-volume-1-eng/ (has 4 chapters)
https://myreadingmanga. info/plug-nagisa-kyou-mo-ashita-mo-asatte-mo-gintama-dj-eng/
here's what i was talking about lol it's harada but not ginhiji
1) http://www.mangago.zone/read-manga/yugami_hajime/
2) http://www.mangago.zone/read-manga/kyoushitsu_no_yugami/
The funny thing is that... from what I can remember, it's Hiji who was the teacher and gin who was the student. And he was kinda desperate to be with Hiji. (ノ≧∇≦)ノ
Update!!!!! I found it thanks to your list!! <3 now I'll be able to sleep in peace. After I read this!
Kyou Mo Ashita Mo Asatte Mo (Yaoi)
yesss that's such a good story!!!! happy to have helped you :)
So there's this DJ, I think, with what look like gintama x hijikata, but like Harada art style or close. But they were teacher x student... I can't remember what is called or find it and already looked through all Harada and others