[1st verse:] Butterfly, you're like a butterfly, baby vampire Thro' the year, you're sipping honey here and there Your love is like a blushing rose It just comes and goes Butterfly, you're just a butterfly, With your string of helpless beaux [Refrain:] Whose little heart are you breaking now, little butterfly? Who is the one that you're shaking now, little butterfly? Who keeps on ringing Your telephone, one-two-three-four? Who keeps on singing "What do you want to make those eyes at me for?" Who sends you candy and flowers now, little butterfly? Spending above what his folks allow I wonder whose feelings you're hurting When he catches you flirting Whose little heart are you breaking now? [2nd verse:] Seems to me, you're like a bumblebee, baby vampire Buzzing 'round, but never settling down, that's you! Why don't you give up stinging hearts? Don't you know it smarts? Taking them and simply breaking them In a thousand diff'rent parts?
https://primoaccordo.net/irving-berlin/whose-little-heart-are-you-breaking-now.htm