Decided to also bulk out Eclair's friends, so here is Parfait first.
Bulking out tends to have a somewhat adverse side effect on Parfait, while she is normally the most friendly and outgoing (if not overly competitive) of the group, attaining such mass tends to mess with her head and makes her feel like she can take on the world. So much so she would force herself into competitions just to win them or force people to compete with her just to feel that competitive spirit burn through her. Not only that, while she is normally only mildly flirty with guys, now she just forces herself upon them and gives them a nice and affectionate (if not tightly gripped) "face moistening", something they really can't escape from. Not only that, her boundless energy wants her to party hard like she hasn't ever had before, barging into any sort of establishment that has any kind of festivities going on and going all party animal all over it.
It literally takes the strength of her equally bulked up friends to keep her rowdiness under control when she has all this "pumped up" energy flowing through her. Which is why she is usually not permitted not to bulk up unless at least one of her other friends is bulked up like her... Or if he is around, Schmucky, since handling someone like her in that state is nothing for him (even when she gets a bit "affectionate", though he has developed ways of subduing her).
She does manage to gain control over this when she grows into an adult, though that energy still persists when she bulks up, so she tries to find creative ways to disperse it, like taking up boxing and beating up reinforced steel column dummies, practice marathon running, and grappling with other female associates at the gym. Of course, if she has some left to squeeze out, give whoever she is dating at the time an AMAZING and exhausting night of intercourse.
Sometimes, having such a physique can be a burden on others, even when you don't mean any ill-will.