Yuri Danshi (manga)

The MC boasts to the wrong person how he is an expert on Yuri magazines:

Double page from the manga Yuri Danshi, showing the MC striking a pose while declaring himself an avid Yuri magazine reader
Double page from the manga Yuri Danshi, showing a black haired girl readying to strike the male MC
Double page from the manga Yuri Danshi, showing a black haired girl readying to punching the male MC in the face, crushing his glasses