Aomine thought it was clever, really. He'd read about it on some website, something with a dog and saliva and other science shit.
It all started when he realized Kagami spent a lot of time in the kitchen. At first he didn't mind, since he was in love with Kagami's cooking. But then he started feeling ignored whenever this happened. Since Kagami would usually be too busy concentrating to pay any attention to him.
And so it started with little things.
Every time Kagami was cooking or doing something in the kitchen, he would call out to him or ask him something. He'd ask what was for dinner, if he could help, is it done yet, ..
It quickly went further than that. Soon he started actually joining him in the kitchen. Subtly brushing his hand on Kagami's arm as he passed by him. A quick peck on the cheek or neck or whatever place on his body that was accessible.
Sometimes he would steal some food, trying to get some reaction out of Kagami. It usually worked, although it was always a slap on the fingers and a "Stop that!" That was fine.
Other times he would sneak up behind Kagami and wrap his hands around his waist. Although Kagami always said he was in the way and couldn't cook properly this way, Aomine knew he didn't really mind since he never made any move to shove him off.
At times he would try to tease him. He'd untie the knot of his apron. Distract him so he could try and steal Kagami's knife or spoon without him noticing. Sometimes even a slap on the butt, making Kagami yelp in surprise.
Sometimes he'd even actually help Kagami in the kitchen, cutting some vegetables or stirring in the pot. That ended up in Kagami chasing him out the kitchen when he burned something more often than not.
What he liked to do most however, was seduce Kagami while he was cooking. He's stand behind him and slide his hands up Kagami's shirt, press his groin against Kagami's butt, his lips attacking Kagami's neck. If he was lucky, Kagami wouldn't mind much and respond by pushing back against him or tilting his head to the side so he had more access to his neck. If he wasn't so lucky, a stomp to the foot or a flick against his head got him to back off.
It was fine either way (though he preferred the first option) since his goal was to get Kagami's attention on him.
See, this is what he'd come up with.
He figured that if he annoyed Kagami enough while he was cooking, get him to pay attention to him while in the kitchen, he would always be on Kagami's mind when he was in the kitchen. Even when Aomine wasn't there.