He gives a little bow to offset that stern look, his ears bobbing cutely. Once he has permission, he takes a fine paint brush and dips it into the paint. Meng Yao used to help his mother with her cosmetics, so this isn't difficult at all.

"I'm sorry if it tickles."

Once he is satisfied - he doesn't give Mingjue whiskers - he rises on his toes to kiss the man's cheek. He is grateful the other is playing along and he hopes Mingjue enjoys himself.