Peridot honestly hadn't been thinking about that possibility at all, so it sort of throws her for a second when Lapis mentions it. But, overall, she seems relieved. Relieved to not have to think about Lapis hooking up with some random human, and relieved enough to make some awkward jokes about it to drive how unsavory a scenario that would be, at least.

"Hah! Right, can you even imagine? A lapis-lazuli human hybrid... What would that even look like? Would it be... Blue!?" She dissolves into uncontrollable snickering, propping her head on one hand.