"Worms?! We don't have worms!" Kili and the other dwarves yelled angrily at Bilbo in protest, feeling betrayed that he would say something like that about them, since they hadn't caught the gaze he had thrown in Thorin's direction.

Rolling his eyes angrily, Thorin gave Kili and the other dwarves below him a sharp kick to warn them to play along as the hobbit was trying to help, and they quickly changed tactics.
"I've...got worms as big as my arm!" Oin announced loudly.
"Mine are the biggest worms, I've got huge ones!" Kili declared somewhat proudly, hoping it was convincing enough.

It seemed to have had the desired effect, for now. The trolls looked positively disgusted and had dropped poor Bombur who had been picked up and was about to be eaten "boots and all" just as he was.
"What would you 'ave us do then?" asked the troll who was named Bert. "Let 'em all go?"