Chekov doesn't even try to protest. He knows that expression-- it's the same as Kirk's had been when they'd gone shopping for shoes.

"Aye, sir," he replies jokingly.

Chekov picks through the racks of clothes. His fashion sense is 'if it fits and doesn't look awful, it goes together.' To be fair, he usually wears uniforms; he even wore uniforms before the Academy, courtesy the universities he went to.

Still, he holds up a green shirt (ha) and black trousers similar to the kind he's wearing.

"Will this work?"