18+ Tamatama Otome♥: Shounen ga Shoujo ni Naru Toki

Yuri is frustrated that her childhood friend, Taku, is not very masculine. She wants to level-up their relationship but Taku just can't make any bold or sexual advances. Then one day an evil spirit (youma) pops in on Taku and tells him about a prophecy foretelling of a time when Taku's offspring will save the world. After finishing the tale, the youma immediately puts a curse on Taku's balls in order to stop the prophecy from coming true. But that curse has made Taku more feminine than ever. Is Yuri's dreams of a love-love relationship with Taku over, or can she help Taku find his masculinity?

(Source: MU)