Valkyrie's willingness to push her advantages was one of the many things Loki decidedly appreciated about her, and another was her unwillingness to back down in the face of a challenge. Even when it was as simple as refusing to back away with no other stakes.

Well, no other stakes apart from the fact that they'd both know he'd won if she did.

They were still in public, so rather than actually lean down to lick a little more powdered sugar off her lips, or pretend to, he just brushed a thumb over her lower lip.