You want fan-service? You got fan-service. Basic story of the manga and the anime is that Densuke Mifune is forced to join the Eiken club, primarily staffed by girls with breast sizes ranging from A-cup (two at 73 and 77 cm) to Harumachi Komoe, a 6th grader with a listed 110 cm bustline and an approximate height of 4 ft. And yes, they do also have the obligatory loli in the series. Densuke continues to wind up in compromising situations with the girls, frequently due to them purposefully forcing him into them. To give you an idea of the fanservice involved in this anime, most of the pictures on the server are screenshots.