He's going slowly red as they talk, a creeping blush that Yellow himself is doing his utmost best to ignore.

"Wh-" He wilts a little after the half-syllable and looks down at his tea again, sipping it even though it's probably still scalding. It is definitely better than making eye contact with his next question. "What if Crichton gets tired of waiting and asks someone else?"

It's clear enough that Yellow has a someone else in mind.