my ass vs us

my ass

pron
  • I; me; myself; oneself in the third person. 

intj
  • Indicates disapproval, disagreement, or disbelief, often with a tone of disregard, disdain, or disgust, referring to the buttocks. 

us

pron
  • Me (in all contexts). 

  • Me. 

  • Our. 

  • Me and at least one other person; the objective case of we. 

det
  • The speakers/writers, or the speaker/writer and at least one other person. 

How often have the words my ass and us occurred in a corpus of books? (source: Google Ngram Viewer )