The situation where one is tied up in one's own jock while wearing it. Leg straps and waistband are stretched and twisted around arms and legs and sometimes, the cup portion is pulled up over the head. Usually seen in high school locker rooms where wrestlers and/or football players hang out. Is used as a noun or as a verb.
Also used to describe the locking of somebody's legs by bending them back and slipping the ankles up through the underwear leg hole or twisting the waistband down over the shoe.
During wrestling practice, they grabbed Ron and in disbelief he struggled as they quickly jock-locked him, wrapping him up in his own athletic supporter like a spider trusses up a fly before leaving him on the floor curled into a helpless, cursing ball.