Well, Stretch at no moment was promoted or described officially as a yuri or girls love or romance manga, it was only described as two girls living together on an apartment and stretching, meanwhile Prism was published on a magazine dedicated exclusively to yuri. Vampeerz is described on the Sunday GX website as: "This is a story of a girl and a girl's little love", so that description already sets the status of yuri, so this series is more like Prism than Stretch