Maid-san no Hon: Boku no Imouto-hen

From One of a Kind Productions:

So, there be a service where you can reserve a girl for your own special service for a fee and a set amount of time. Also apparently, the “little sister” is the most popular girl out of all of the potential girls. So, it’d be tough to get a reservation for her. Luckily, the guy managed to get that reservation…