Source: birdyhugsok headcanon
bear with me here
ok so you know how now we’re like OK TROLLS HAVE BOOBS
but obviously since trolls don’t breastfeed or raise their young at all, they don’t use them for the same purposes
when meenah talked to meulin, meulin started squealing, and meenah told meulin to “clam those rumble spheres”
later on, in tags, meenah tells her to unclam those tatas
so right now we know that boobs = rumble spheres
rumble spheres. what if female trolls use their troll boobs to purr and while meulin was screaming her boobs were purring
ok that was an interesting sentence. boobs purring
but there we go. trolls can purr. or at least the females can. who knows. maybe male trolls purr too but their rumble spheres are small