Osomatsu-san

Synopsis

Looking to earn some easy money, Iyami and Chibita set up their own "Rental Girlfriend" business, which gets no business due to how ugly they look. To their end, they take an experimental drug from Dekapan and transform them into cute girls that manage to catch the attention of the Matsuno brothers. The pair soon use their now feminine wiles to charm the sextuplets, hitting them with various hidden fees to make a lot of money. However, the drug soon starts losing its effectiveness, causing them to lose their female forms during a final date with the brothers.

(Source: Wikipedia)