If Yuuri was actually teasing, he could never do this. But this skirts the line between play acting and the truth. He really is feeling all the things he's feeling, the shyness, the not knowing how to approach this with Viktor, like he's out of place. The only secret is that Viktor doesn't know he's determined to not let any of that matter.

So he flushes and looks away, embarrassed, but manages to get out,

"Yeah. That's what I just said. I'm not..." no wait, that's too much of a refusal, so he forces out, "Viktor, none of my clothes match it."