cod-piece (n.)

also codpiece, mid-15c., in male costume c. 1450-1550, a bagged appendage to the front of close-fitting breeches, "often conspicuous and ornamented" [OED], from Old English codd "a bag, pouch, husk," in Middle English, "testicles" (cognate with Old Norse koddi "pillow; scrotum") + piece (n.1).