BSN here! This is Emons's "Kouya de Gangan", a short story featured in 2D Comic Magazine Ganimata Kaikyakude Kutsujoku Acme! Vol. 2. Enjoy! (Translated by BSN)
NOTE: You can find all of my uploaded works including my fjorded/expunged stuff from Ex at my blog here: https://bsnscans.home.blog I will update it with every new release, including new loli/shota content.