shoot one's cuffs

verb1

1. •
   To straighten one's arms with a sudden movement to make the cuffs of one's shirt appear beyond the sleeves of one's coat or jacket.

   • Take a pretty young man from behind the desk or the counter. He must be possessed of consummate vanity. Teach him to shoot his cuffs, square his elbows, and brandish his pocket handkerchief. — 1875