Sequel of "Soften up♀ a stiff you♂". Lui, an earnest high school boy, is turned into a girl after being possessed by a succubus named Lily.
Furthermore, with Lily’s power, Lui’s surrounding environment is altered as if he has always been a girl, in which he reluctantly lives as now. Due to Lily’s influence, Lui can’t suppress his sexual desire resulting in masturbating and having sex with his former best friend from when he was a boy. As he repeats these things, gradually a change in heart also begins to show...

(Source: Fakku)