If he were to be true to himself, which he generally isn't when it comes to this shit, Derek knew he was fucked the very first time he met Stiles Stilinski. Or no, actually, that's not entirely accurate—it was before that.
Derek was fucked the second he smelled the kid's unique scent hitching a ride on the damp breeze that cut through Beacon Hills preserve on that fateful day. It was just over two years ago when Derek stood on his family's land and tapped a claw against the plastic casing of the inhaler he'd found; the inhaler he'd sniffed out from the undergrowth in the middle of an early fall night; the inhaler that sat in the pocket of his dead Dad's leather jacket, the one he'd recovered from the ruins of his childhood home, still smelling of smoke and ash; the inhaler he'd returned the day after he'd decided to play pretend with himself that it had been him who had bitten Scott McCall.
Derek haa been pretending ever since.
But how is he supposed to play dumb with the rogue piece of Stiles's clothing screwed up in his fist, and him finally home alone in his own apartment? Worse (or better) is the fact that it's the kid's favourite, the one he wears all the goddamn time. How can Derek fool himself into thinking the thing seen the inside of a washing machine in the last month when it reeks of nothing but pure, unadulterated Stiles?
That red, red hoodie.
Derek's eyes flash blue to remind him of who he is. At the same time as his fangs drop, his short nails extend into yellowed-black claws. Absently, he thinks of Little Red and The Big Bad Wolf as he lets his form shift, his resolve shattering like mirror glass as he accepts his seven years of bad luck with grace the moment he shoves his face into the fabric. He releases a throaty groan that turns into a low growl before morphing into a sex-hungry, shuddering snarl.
Then he breaks and inhales Stiles's scent, fervently, feral. Deep; deeply; deeper... and Derek is forever lost to Stiles Stilinski.
.
(from my current sterek WIP—let me know in the comments if you'd like to be tagged when it's up!)