Heard Costello perform this song as a concert opener in 1977.
I'm pretty sure the first line (repeated in subsequent verses) is:
"She can roll her shoulder, she can roll her ass."
It not only fits with the syntax (third person, present tense) of the next line, but it also rhymes ('arse' doesn't rhyme with 'lass'; 'ass' does).
- Agreed. --Nunki 21:17, 23 September 2006 (CDT)