Thankfully for Minami, Yuuri is also processing slow at the moment, or he might have jerked the cake away. As it is, there's enough time for him to realize that this... probably looks way more intimate than is polite and to regret all of his life choices, flushing prettily with the realization, but not enough time to actually move

"Ah! Sorry, sorry, I..." he flushes more, "I'm just... I'm used to America now, I didn't mean..." he hands him back the fork, trying to sink through the floor a little bit. "Please forgive me," he uses a really probably inappropriately formal apology, considering Minami's his junior.

Then again, he's also not reclaiming space like he normally would be.