Uemura-Kun Ha Majime Na Iiko summary:

To his teachers, classmates, and parents, Uemura is a model student. But, that is hardly the truth. Beneath his serious exterior, Uemura loves masturbating more than anything else and spends his day thinking dirty thoughts. His facade as a serious student slips when his playboy underclassman, Matsuoka, catches him at school jacking off to dirty panties. Has Uemura finally found someone who can accept his true self?