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...
The porn-mag strategist is overthinking 
things to the point of not making sense.
استراتيجيّ إخفاء المجلّات الفاضحة تعمّق في تفكيره لدرجة أعجز فيها عن فهمه
El estratega de revistas porno le da tantas 
vueltas al asunto que ya no tiene sentido.
O estrategista pensa tanto que
 começa a nem fazer sentido.