Isekai Kita node Sukebe Skill de Zenryoku Ouka Shiyou to Omou The Animation

Episode 4

In order to defeat the Demon King, the goddess uses her pussy to sexually train Tatsuo even if it means going crazy with pleasure. The Demon King, after seeing how the goddess and Tatsuo fucked, asks Succun to transform into the hero to have sex with her.