This was written in response to a fanfiction challenge at WIKTT.  The beginning two paragraphs and part of the third paragraph are not mine, and the last part of the last sentence isn't either.  This is meant to be a short vignette, and I will not be adding anymore to it.

A scream rent the silent night air, startling the young lady in the Head Girl's room awake. Eyes rapidly scanning the room, she searched for the source of the banshee howl. Seeing nothing moving within the room, she gently nudged her companion. Screams in the night were not unusual at Hogwarts School of Witchcraft and Wizardry—what with the large population of ghosts and other fantastical beings, but something about this one made her tremble with fear. The one sharing her bed was still sound asleep. He made a sound very much like a sigh and shifted position, but other than that showed no signs of stirring.

"Wake up!" Hermione Granger said, poking more firmly.

His eyes finally opened, and he opened his mouth as if to speak.  Instead, he yawned fiercely and rolled back over, the clock in his room chiming two. 

"Merlin's Beard," Hermione mumbled the curse, and gave her partner one hard shove.

"Gods above, Hermione, what is it?" Professor Snape asked of his bed fellow, as he sat up in bed.

"Someone's screaming," Hermione stated, as another sharp yell pierced the air.  "What is it?" Hermione asked, trembling a bit.

"It sounds like Peeves has hold of Mrs. Norris again," Snape told her, sleepily. 

"Oh," Hermione said.  Laying back down, she reached her hand over to her companion's thigh, and fingered the edges of his black silk boxers.  In response, he gave a sigh that was a mixture of happiness and aggravation.

"Must we do this now?" he asked.  "I was sleeping."

As Hermione's head crept higher on his thigh, all thoughts of sleep left his mind.  "If you insist," he muttered, as he captured her mouth with his.  And Hermione did insist.  Again and again and again.

Needless to say, Mrs. Norris' screams were not the only ones piercing the air that night.

Finally exhausted and satisfied, and with the clock chiming six, sleep overtook the two in the bed.

El Fin