Severus waited impatiently for Lupin to finish in the restroom. He was chomping at the bit to hear all about Lupin's transformation, and if his potion had any sort of affect on it. Severus' squinty eyes darted towards the bathroom door, imagining Lupin slowly stripping his clothes off inside, and stepping into a warm shower. He imagined soapy lather sliding down Lupin's body and over his skin...
Severus slammed his fists down onto the top of the desk, rattling the things that were scattered onto it. He closed his eyes and took a few deep breathes to calm himself. This was quite ridiculous, and the back of his mind said viciously to him that Lupin must have put some sort of spell over him to have enslaved his mind so easily to such desires.
He knew it wasn't really true: He was a man the same as any, and had often been deprived of affection, touch, desire, and so perhaps he craved it once he tasted it, more than others might. Snape ran his fingers through his greasy hair to straight it a bit, and waited for Lupin to come out.