Rating: PG-13, to eventually become NC-17.
Ginny/Severa Snape...yes, Severa. See disclaimer.
J.K. owns everything except me. I'm not making any money off this, so you can't sue me. Nyah.
This fic requires a bit of explaining, since the character Severa Snape does not exist in canon. This is based on a challenge from the LJ community hp_girlslash, where Severus and Harry become Severa and Harriet. For some reason, Severa/Ginny appealed more to me, so here's what you get.

“Ten points from Gryffindor, Miss Weasley, for tardiness. Again.”

Ginny, red-faced and sweaty from running through the dungeons, slumped down into the last empty seat next to Colin Creevey. He smiled at her sympathetically before turning his attention back to his slowly bubbling cauldron.

Ginny began to chop up ginger roots, noisily slamming her knife back and forth across her desk. “Bitch,” Ginny mumbled under her breath. If only Professor Snape were under her knife. Her nose did kind of look like a ginger root, though, and the thought made Ginny smile.

“Another ten points from Gryffindor, Weasley.” Snape had somehow materialized at Ginny’s elbow. Snape’s hard mouth twisted into a snide smile as she leaned close to Ginny’s ear. “I will not tolerate insolence.”

Ginny let out a loud sigh and continued to roughly chop her roots. Snape stood. Her tall angular frame cast a shadow over Ginny’s desk.

“I want all of you to survey Miss Weasley’s work,” Snape said, looking around at the class. There was a hint of laughter in her voice. “So that you will learn exactly how not to finely dice your roots.” The Slytherins in the class snickered.

Ginny wished she could disappear. “Professor Snape, I was just trying to --“

“Another ten points from Gryffindor for sloppiness.”

“-- catch up since I was so late --“

“Silence, Weasley!” Professor Snape’s mouth stretched into a thin line. “Another ten points! And a detention!”

“Forty points!” Colin squeaked.

“It’s a miracle -- Mr. Creevey can add.” The Slytherins laughed heartily as Colin buried his face in his hands.

The rest of Potions was uneventful, and for this Ginny was grateful. After the lesson she tried to slink out of the room with the rest of the class. Snape glanced up from paperwork on her desk.

“Miss Weasley, kindly stay behind so that we may arrange your detention.”

Ginny grimaced, but approached Snape’s desk. “Yes, Professor Snape,” she mumbled.

“I have just received a fresh supply of Billywigs. You will join me here after dinner to remove and preserve the stingers.”

Ginny nodded and started to back away, when Snape suddenly reached over her desk and touched Ginny’s cheek. She brushed her fingers tenderly over the soft, pale skin. “Such a pretty face,” Snape said softly. “It’s a shame.”

Ginny took a step back. “Wha - what is a shame?”

“That you’re a Weasley,” Snape said simply, black eyes glittering.

Ginny turned and ran out of the room, out of the chilly damp of the dungeons. She rubbed her cheek, scrubbing away Snape’s cold touch, and the flare of heat that followed after.