Mint na Bokura

Noel has a close connection to his twin sister, Maria. When Noel learns Maria's gone to a boarding school to be near her first love, he goes after her to stop it. The only problem is that the school has only one bed left, for a girl student. Disguised as a girl, Noel attempts to bring his sister home. In the process, love is found, lost, and found again for both of them.

The twins Maria and Noel have always lived together and are very closely linked. When Maria decides to enter Morinomiya School because of the beautiful eyes of its basketball coach, Noel, who refuses to be separated from his sister, decides to enter the same establishment. Unfortunately, there are no spots left for boys. He thus decides to pass himself off as a girl! But school life is not easy when one must constantly play in a comedy! Especially when Noel rapidly falls in love with Miyu, a fellow classmate, while he himself is courted by another student.

There are not really 16 volumes. There is really 6 but the scanlation was done from the Spanish version and it was released in 16 small volumes. Each volume is about 2 chapters.