Cupid no Itazura (2006)

Original title: クピドの悪戯

A man who's still a virgin, has a very very rare disease which allows him to only have sex seven times in his life. After he has used up all the seven chances, he will never ever be able to have sex again for the rest of his life... and so far, he has wasted two times on 'self gratification'. Now he only has five times left, and he wants to choose carefully and save himself for that someone special...but at the same time he desperately wants to lose his virginity...