[MIMK-117] Furachi – No. 1 doujin that won the triple crown! I Shouldn’t Fall In Love With The Resident Of The Opposite Room And A Convenient but Bad Relationship – Riho Shishido

The main character (Ken) regularly spies on the neighbor lady (Shishido Riho) using binoculars, as she has a habit of masturbating furiously, and he uses that as fap material as well.

However, one day in the street, she bumps into a lady having problems with a bike and shockingly discovers that it’s the same lady. This icebreaker triggers a new adventure between the two.

The original is called Furachi and was done by Urasuji Samurai. And yeah, it was a bestseller.