Might've been better with Pichu, considering the whole self-inflicted damage thing.
I think Yayoi is just frightened when she uses her "Peace Thunder"...You can see it in episode 38,when Chibi Cure Peace tried to use "Peace Thunder",but got surprised and fell,before she whimpered,saying she got frightened(bikuri)...Ignore the subtitle from the show,as I can see that the subtitles are not accurate...
