Her Sin

Aoi and Sato are dating, but somehow struggle to get to the next step of their relationship. One day, they get physically close in an empty classroom. Aoi is determined to go all the way next time, but little does she know that the bad guy of the class saw everything...

(Source: Coolmic)

Notes:
- Originally self-published as two separate works, Kanojo no Okashita Ayamachi (彼女の犯したアヤマチ) and Kanojo no Okashita Ayamachi -Zoku- (彼女の犯したアヤマチ -続-).
- The two chapters are split into 8 ‘episodes’ in the longstrip version.