Peridot is just mortified that she's acting this way in front of guests. In front of her potential future teacher, no less.

...Then she catches a glimpse of that grin and. Hm. Well at least he's not actively disapproving of this whole display?

"Please don't encourage her," Peridot growls at him, breaking her death glare directed towards the kitchen long enough to shoot him A Look. She's just going to tap her foot impatiently, waiting for Miko to reemerge and disappear back upstairs again so that they can get on with this spell already.