Ruma is the most beautiful and popular girl on school, she acts nice and polite with her classmates and friends, but she has a side that almost every male student knows and that is that she has the perfect sex body and she likes to have sex with any student she wants, where she wants and when she wants. Actually she only feeds with the sperm of her sexual encounters. The couples from Stringendo &amp; Accelerando also appear in this OVAs and are Stretta's photo-targets so she can masturbate later with their sexual encounters.
 
(Source: Anime News Network)

1-2) Boku wa Benkyou ga Dekinai (僕は勉強ができない); Comic Mujin 2004-10, 12 
3) MBJ: Mizuho-san Chi (MBJ-みずほさんち-); Comic Mujin 2005-08 
4) Issen (一線); Comic Mujin 2006-01 
5) Bed no Nukumori (ベッドのぬくもり); Comic Mujin 2005-04 
6-7) Aruiwa Mononoke (あるいはもののけ); Comic Mujin 2008-04, 08 
Girl puts out upon request only once per guy, because her body is made for sex.