Puberty Study SessionShishunki No Obenkyou; Puberty Study Session; 思春期のお勉強; Onee-chan ni Makasenasai!; Leave It To Onee-chan!

Kasuga is very interested in penises that she cant concentrate in class. Her childhood friend Kobayashi teases her unknowingly and challenges her that whoever scores worse in the next test has to obey an order from the other. Kasuga immediately sees an opportunity to look at the real penis shes been dreaming of. --- - Link to The Doujinshi & Manga Lexicon - [Chapter 5](https://www.doujinshi.org/book/1666808/COMIC-Shingeki-2019-05/)