To slit someone's throat by swinging your
knife/
shank/etc. is a arc that mirrors a smile and buryinng the
knife into the victim's throat.
"I got
business to attend to-I've got smiles to cut." Bellowed Iggy.
"You like a smile?" Candy said quietly.
And then her
hand swung up in a silvered arc and she buried the
knife in his throat.