Welcome to the N-H-K (2006)

S1E3 Welcome to the Beautiful Girl!

Tatsuhiro unexpectedly finds out that his loud otaku neighbor is actually an underclassman he remembers from high school. They come together to collaborate on creating an eroge (erotic game). To kickstart their project, Tatsuhiro decides he needs some inspiration and delves into the world of eroge himself. However, he quickly becomes engrossed in the risqué universe of bishoujo, or "beautiful girls."