Gin-san takes history lessons, and teaches you how to hide your porn mags?
Tsukuyo tries to teach Seita history, the subject he's not great at. However, her training (?) methods end up leaving him scarred, which makes desperate Seita ask Gin-san to take over as his tutor...
That's what you get for having 
perverted thoughts all the time.
هذا ما تجنيه من فكرك المنحرف على الدوام
Eso nos pasa por pensar en 
depravaciones todo el tiempo.
Quem manda só pensar em besteira.