One on four vampires

One dark, late night, Cosmo was walking down the street. He turned onto an alley and froze in place, dodging an unusual scene: four real vampires had killed a man and were drinking his blood. They noticed Cosmo standing there and then abruptly ran away. He ran as fast as he could, but they caught up with him. They didn't want to kill him, so the tallest vampire, Sprout, picked Cosmo up and teleported somewhere, followed by three more vampires. Cosmo remained unconscious until he woke up in bed. "Where am I? " he whispered, "What am I, a femboy?" Cosmo thought, seeing himself in a pink minidress, until four vampires appeared. The eldest was Sprout, the slightly younger was Dandy, the middle one was Astro, and the youngest was Louis.