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...
You're great at teaching 
the Hyakka new techniques,
أنتِ تجيدين تعليم الـ هياكّا مختلف التقنيات
Como eres tan buena enseñándoles 
técnicas a las Hyakka,
Você é ótima para ensinar
 novas técnicas à Hyakka,