have calluses from patting own back

have calluses from patting (one's) own back

To have excessively praised oneself for an achievement or a job well done. Tony was instrumental in the success of the merger—or so he says. I bet he has calluses from patting his own back.
See also: back, callus, have, own, pat
Farlex Dictionary of Idioms.

have calluses from patting one's own back

 and break one's arm patting oneself on the back
Fig. to be a braggart. If you haven't heard about Bill's latest achievement, he'd be glad to tell you. He has calluses from patting his own back. Jane: I did a really wonderful job, if I do say so myself. Tom: If you're not careful, you'll break your arm patting yourself on the back.
See also: back, callus, have, own, pat
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • wash (one's) hands of (someone or something)
  • wash hands of
  • wash one's hands of
  • wash your hands of
  • wash your hands of somebody/something
  • wash your hands of something/someone
  • for (one's) (own) sake
  • for sake
  • keep in sight
  • keep sight of (someone or something)