Red-figure calyx-krater, attributed to Euphronios, ca. 500 BCE. Berlin, Antikensammlung F2180. 

Red-figure calyx-krater, attributed to Euphronios, ca. 500 BCE. Berlin, Antikensammlung F2180. 

This is an athletic scene, and the figure to the far left is infibulating himself. This was a practice where men would tie their foreskin shut with a string known as a kynodesme (κυνοδέσμη) before they exercised out of politeness. While this practice is mostly associated with athletes, older symposiasts are also shown on pottery as infibulated.