It's early Spring in their sixth year. Hermione and Ron have been prefects for their fifth and most of their sixth years. They like the responsibility. Hermione likes it because she has the chances to be bossy with younger students who have to pay attention. Ron is following in Percy, Charlie and Bill's footsteps. He looks up to them, at least to Charlie and Bill. They both enjoy the few privileges being a prefect brings. The first and most obvious is the use of that bath on the fifth floor. The one just past the statue of Boris the Bewildered. Harry Potter, the other three Quidditch team captains and some others with responsible positions have privileges in that bath, too.
No, they don't use it together. Boys and girls use it in turns. Each gender gets the privilege at some time of each day. That time changes around from day to day and week to week. It's one of the head girl's duties to make up the schedule.
The head girl is Rhonda, a seventh year Ravenclaw. She's sharp. Her face has sharp features and her mind works with sharp logic. She learns eagerly and likes to show off what she's learned. She got eleven O.W.L.s with ten 'O' marks. She's also bossy. Is that a characteristic that makes a good prefect? She and Hermione have so much in common they can't help but be friends.
This is the time of year when fifth-years are worried and studying hard for their O.W.L.s. Seventh years are doing the same for their N.E.W.T.s. The sixth years have only to worry about detention from Professor Snape and just what Draco Malfoy is doing in the Room of Requirement. Poor Harry.
Rhonda is as intense and fretful about her exams as Hermione was. She asks the younger prefect for a favor. Rhonda asks Hermione to make out next week's bath schedule and distribute it to all those who use that luxurious facility. Hermione eagerly agrees. She sees this as a way to do something she'd have to ask of Rhonda as a favor.
Hermione has finally unwrapped Ron Weasley from around Lavender Brown. That's not all she wants, though. She'd much rather have him wrapped around herself than acting like just a friend. She's been scheming and developing a plan. Now the means has fallen right into her lap - literally. She's sitting under a tree at break with a parchment on her lap and quill in her hand. She doodles around a grid of days and hours.
She finishes quite a good schedule. There's enough variety from last week that nobody is stuck in a rut and everyone has convenient hours. She makes copies later in her room. There is one point where her scheme has come into play. The last two hours of the day are more desirable than other times. That's when they can relax in the warm fragrant bath at the end of the day just before bedtime. Those last two hours Tuesday evening don't read the same on all the copies of Hermione's schedule. Some say Tuesday 10pm - Boys, and some say - Girls.
Hermione writes names on the parchment so she's sure everyone gets a copy, and they get the right one. She writes girls' names on the ones that say - Boys. She writes boys' names on the ones that say - Girls. There are exceptions. Ron Weasley gets a schedule that says Tuesday 10pm - Boys. Hermione Granger gets one that says - Girls.
She sits on her bed, holds up her own copy of the schedule and admires it. She's sure this will work. She starts to imagine what will happen. She imagines the sights - all set in the luxurious bath. She imagines smells and fragrances, and only some of those come from the perfumed bubbles. She finds that her imagination works as usual this time. She's feeling something of a tingle. She decides to take care of that and indulge herself in the usual way.
Her robe and skirt come up. Her hand goes down inside her panties. Her other hand wraps across her chest and squeezes her breast. Fingers between her legs go to work on what they're touching. Tingles build all over Hermione and she starts gasping. She's soon squealing trying to hold in screams. She just reaches her climax with a finger deep inside herself and two others pinching a nipple through her sweater.
"Hermione, you just have to help ... Oh!" Ginny Weasley bursts into the room.
"Aaaaah!" Hermione lets it out and falls back on the bed.
At least Hermione finished herself well enough. Now she's embarrassed at being caught by Ginny. She's beet red all over. Some of that is left over from her orgasm, of course. She looks at Ginny with a horrified expression and stammers.
"Don't worry. Thoughts of Harry have me doing the same thing when you're not here. It's Ron with you, isn't it?" Ginny lets her off the hook. "We do have some questions about Arithmancy if you get the chance. In the commons."
Tuesday evening comes along without too much special. We don't call any evening at Hogwarts 'ordinary' do we? Harry has no detention, so he's off with the Marauder's Map to skulk around the Room of Requirement. Hermione checks over Ron's homework, marks the corrections and gives it back to him to re-do. At almost ten o'clock, Ron stretches, says goodnight and mumbles something about a bath. Hermione chirps a quick 'Good night' and dashes for the girl's dormitory. Her scheming has worked and now she only has to spring the trap.