Derek hates when Stiles licks his lips in front of him.

He also happens to love it.

And Stiles does it all the time, too. Constantly. Before ever saying a word, that kid is swiping his tongue out, running it over his chapped lips. As if he couldn't speak without his lips freshly wet. As if he isn't aware of how it drives Derek crazy.

Because every time he does it, Derek ends up focusing on his mouth. And when he focuses on his mouth, he starts thinking about his mouth. And what Derek would like to do with that pretty little mouth of his—with his own, and perhaps some other things.

And that's the problem, because Stiles is constantly talking. That kid never stops talking; he's like the Energizer Bunny on crack. So he always has his tongue out, always rubbing his lips together, right in front of him.

Sometimes, Derek just tunes out what Stiles is saying so he can watch him better. And it's not as if he's not going to repeat himself, so Derek will eventually get the point. It's just that he enjoys thinking of ways to stop that obnoxious habit Stiles has.

So perhaps it isn't too surprising that Derek doesn't like it when Stiles tries to break the habit himself.

The kid starts buying chapstick. Derek never knew how much he could hate such a simple little thing. Just a small, thumb-sized tube of pink goop. But Derek hates it. Because Stiles doesn't lick his lips when he has that stuff. Nope. He'll just hastily apply it, pop the cap back on, and play with it while he's talking. A quick swipe of his hand against his mouth isn't nearly as fascinating as the way Stiles so enticingly runs his tongue over his lips.

No more teasing lip-licking for Derek. Nope. All he gets now that Stiles has this chapstick obsession—because the damn kid never goes anywhere without it nowadays—is the way he plays with it while he's talking. And not that watching Stiles' hands isn't interesting, it just doesn't come close.

So Derek resorts to drastic—if rather immature—measures.

He starts stealing Stiles' chapstick.

The second he puts one down on the table and turns his attention, Derek will swipe it away. And Stiles is so unfocused all the time, he never even notices. Out of sight, out of mind, apparently.

Derek begins making excuses to manhandle the younger boy, just so he can get close enough. And while he squawks and yelps and snaps, he never notices Derek's hand slipping in his pocket and grabbing any chapstick he has. If he's in Stiles' Jeep, Derek will take any that is being kept in his cup-holders or console nooks. It doesn't take long for Derek to find Stiles' hidey-holes, and soon they're all ransacked of lip balm.

And Stiles never catches on. Many a time, Derek will watch Stiles frown and feel his pockets, fumble through his backpack, and check under the seats in his vehicle. He gets this frown on his face, and then a look of disbelief, a look that says not again. I couldn't have lost another one. And that in itself is quite amusing, but soon Derek gets his reward.

Stiles eventually gives up buying chapstick, figuring it's just a waste of money if he's going to lose every single damn one he buys. And he goes back to that lovely lip-licking habit of his.

Derek feels quite accomplished of himself when that happens. Without even having to say anything, without anyone being the wiser, he gets what he wants.

He just hopes that no one ever happens to find his questionably large collection of cherry-flavored lip balm that he keeps in dresser drawer beside his bed.