The Common Room
It's the Christmas holidays and Harry, Hermione, Ron, and Ginny are in the Gryffindor common room, enjoying the brief respite.
Harry and Ron are playing wizard chess, with a couple of first-years watching them avidly. Ginny and Hermione are in front of the fire, one large blanket over their laps as they sit and read quietly -- Hermione a dusty tome on Transfiguration Theory, and Ginny one of the more popular wizarding novels.
Hermione's hands are steady on the book, turning a page every few minutes or so as she props the book open on her stomach. Ginny has the book open between her fingers, and she has one hand under the blanket, keeping warm.
The fact that she's keeping it warm between Hermione's legs is entirely secondary.
Hermione bites her lip and looks studious, but she's trying not to twist under Ginny's hand. Ginny's too deft at this sort of thing for The Girl Dating The Boy Who Lived, but Hermione's not going to tell, not going to talk, not going to start swearing and screaming Ginny's name as she begins to tickle her finger on Hermione's clit...
Ginny doesn't even look her way, doesn't even respond to Hermione's faint pants and one hand sliding from Transfiguration Theory to under the blanket and lifting it up just far enough for Hermione to cup Ginny's breast. Each time Ginny twists her finger, Hermione squeezes and Hermione's just about on the brink -- of orgasm and screeching in frustration at Ginny's perfectly calm and composed expression. Ginny flips a page and pushes a finger underneath Hermione's knickers at the same time.
Hermione's sticky and hot and she swivels her hips slightly for more pressure and she's biting her lip and coming so silently that the boys, when they glance over, just think she's reading a particularly interesting passage. Instead of Ginny breaking new territory in an entirely different passage.
Ginny's nipple is rock hard when Hermione pulls her hand away. She shakingly picks up her book again, and when she feels Ginny's eyes burning lustfully at her, she smiles and turns the page.