Don't Say that to Benten {Benten-sama ni wa Iwanaide}

A mischievous pixie-cut heroine and her besotted friend find themselves at the center of a chaotic stunt when the heroine's gown is rigged to burst open on a crowded train. A smirking masked antagonist forces the humiliated boy to either swallow a shrinking pill or plant a kiss on the girl to return her swollen chest to normal. The story flips between breathless panic, leering onlookers, and the masked villain's teasing commands until a plucky caped newcomer called "Sanadaman" swoops in to save the day.