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.
have calluses from patting one's own back
and break one's arm patting oneself on the backFig. 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.