The first time it happens, Derek comes home to a mess. It seems like every single pot and pan he owns is in use or already dirty, and he stands there staring for a full minute before Stiles spots him.
”Hey! Perfect timing! Come taste this sauce. Is it too salty? I can’t tell.”
A million different thoughts whirl around in Derek’s head, and he tries so hard to come with with a way to convey the sheer WTF factor of it all. But then Stiles gestures impatiently with the spoon he’s holding out.
Derek goes to taste the sauce.
It happens again, and this time Derek does manage to ask what the hell he’s doing there. But Stiles has been getting a lot of practice at talking his way out of direct questions, and he delivers a long-winded speech about Derek’s kitchen and Stiles’ cooking skills and the importance of healthy meals, and before Derek knows it he’s once again left with a full stomach and dishes soaking in the sink.
It becomes a thing, and Derek isn’t even surprised anymore. He’s also not annoyed anymore, he realizes, as he watches Stiles drop half a bag of flour down his front, too busy talking animatedly about college choices and dead languages to pay attention to what he’s doing.
Derek kisses him, then, and doesn’t even care that Stiles leaves flour and lumps of dough in his hair.
It comes out in the shower they share later anyway.