Searchin' for my lost chigger of song

The story:

We were driving in the car and I challenged my mom to sing all the words to the song, when she came out with this line.
I instantly cracked up at her and told her it was shaker of salt, because, y'know, Margaritas have salt on the rims. And she argued with me for about ten minutes that "chigger of song" was some sort of drink container they use at bars.
I wasn't convinced, because the only chiggers I know of are tiny flea insects, and she finally gave up and said she would figure out what it was later.