Harry Potter and the shampoo blurbs quoted are not mine, obviously. Written for scifichick774's birthday exchange

June 2, 2000

His best ideas had usually come to him while bathing—"Weasley is Our King" had practically composed itself one Thursday evening while having a lovely soak in the Prefects' Bath. He'd often wished that inspiration would choose another location to visit him, as he'd never been able to find a charm to prevent pruny fingers. However, as Malfoys were best known for the brilliancy of their hair, and not their minds, he'd long ago decided that wrinkled fingers were a small price to pay for occasional flashes of genius.

He'd been in Hermione Granger's (entirely too small) tub for nearly half an hour—he'd had to cast a heating charm twice—and he still had not thought of a remedy for any one of his many problems:
1. He'd had drunken sex with GRANGER (rather energetic drunken sex, judging from the bite marks on his neck and the scratches on his back) and he wasn't entirely sure where he was. Her flat was odd mix of muggle and magical decor, and he thought he might be somewhere in muggle London.
2. She had obviously left while he was still sleeping—actually running away from her own flat in order to avoid him. So much for Gryffindor bravery! She really ought to have stayed and healed his back, at least.
3. His hair had gotten hopelessly mussed and sweaty last night, and Granger hadn't any suitable shampoo. Some vile muggle liquid that promised to "control frizz all day" (this was obviously a lie, as Granger's hair had been as wild as ever). Clearly, this was entirely unnecessary, as he'd never had frizz a day in his life. His hair was always sleek and well-behaved, the product of centuries of careful breeding, and had always been accustomed to the finest of hair-cleansing potions.

After another five minutes, he decided to follow Granger's example and simply flee the entire situation. It would never happen again, of course—he didn't want it to happen again—and he rarely saw Granger these days, as they hardly moved in the same circles, so there would be no awkard social encounters. He decided to use the anti-frizz concoction, as not washing his hair would be completely uncivilized.

His hair felt heavy and limp the rest of the day. Stupid muggle shampoo.

September 20, 2000

He couldn't believe he'd ended up here, in Granger's ridiculously inadequate muggle bathroom, again. He couldn't blame it on too much Old Ogden's this time; he'd had just enough to feel sufficiently reckless and daring to corner Granger on her way to the lavatory. He'd told himself it was only to taunt her about her cowardly retreat. It still rankled, that she'd slunk away from him like that. Surely, after all they'd experienced during the war, he'd deserved better than that; she ought to have had the decency to tell him to his face that she thought it had been a mistake.

He'd never got the chance to say much of anything, though; as soon as he'd gotten close to her, she'd reached up and pulled him into a kiss as she apparated them both into her bedroom. It hadn't been his intention to do this again (though he'd certainly wondered if the sex had really been that good, or if he'd just been that drunk) but he'd been unable to push her away.

He'd woken up first, this time; she'd hardly stirred as he disentangled himself and headed to the bathroom. He had no idea what to do now; he was torn between waking her up for another go (it really had been that good!) and checking himself into St. Mungo's. In the end, he'd decided to just take a bath and see if any better ideas came along.

He ended up sitting in the bath for an hour, until the water got cold. He could not get involved with Hermione—the first drunken shag had left him confused enough as it was. Potter and Weasley would kill him, if they ever found out. His mother would either disown him or kill Hermione. It wasn't as if she'd ever bothered to contact him after the war. She'd never visited him in the hospital after the last battle, but she'd sent him flowers. She'd submitted an amicus curiae in his defense that must have taken weeks of research, but she'd not bothered to attend the trial. That was it. He was going to wash up and then leave—and not because he was scared, but because he was done with her. She could see how it felt, to be the one left behind, in a bed that reeked of sex, wondering what you'd done wrong.

The shampoo was different this time; it seemed she'd given up on the anti-frizz efforts (not that he'd been able to tell any difference). There was some weird shimmery brown sludge that promised to give "truer, multidimensional brunette tones" and there was no telling what it might do to his platinum blond hair. He used something called "body wash" instead…

Which was a big mistake. His hair was oddly sticky and smelled like flowers all day long.

November 1, 2000

This really would be the last time. In future, if he saw Granger anywhere alcohol was served, he'd be apparating, flooing, flying, or, as a last resort, running, away as fast as possible. She'd left him, again (and how pathetic was it sneak out of your own bedroom?). This time, though, he'd wait until she got back and then he'd tell her exactly what he thought of her childish, cowardly behavior. He'd—

The shower curtain opened, and a bashful looking Hermione, very sloppily dressed, handed him a yellow bottle, made out of that odd muggle material "plasstik" or something. The label promised "glistening blond highlights" for platinum to champagne blonds. She stood there, smiling nervously, and explained that she'd popped out to get it for him. He continued to stare at the bottle, dumbfounded, until inspiration finally struck (his best ideas always did come while bathing, after all). As he was somewhat unfamiliar with muggle shampoo (maybe he'd been using it wrong, those other times) he invited her in to supervise.

Her bathtub, which had seemed too small for one, was exactly the right size for two. And his hair was brilliant and shiny and soft all day.