When a Police Officer or other authority figure representing a government or private entity searches you by using his or her hands. This is usually done to hot, boobular females by both male authority figures and females who would rather the touch of a woman's body to that of a man's. In most cases after cop a feel is completed the female and or male being "copped" is let go unless a serious felony has occurred. "Cop a feel's" usually only occur when an authority figure is bored and or horny.
Barbara felt kinda turned on when the female police officer pushed her over the trunk of her car, spread her legs and did an in depth cop a feel.
To feel up a girl when she isn't expecting it, that is, grasp her tits or grab her in the crotch (and if a finger shud happen to enter her vagina, so much the better !!)
Best time to cop a feel is in a crowded place so you can run off and can't be found. When I went to my family reunion my 3rd cousin once removed was in a crowd and her juicy peaches were calling me, so I ran up, coped a feel and ran away to the punch table 2 aisles over. Later in the day I grabbed her crotch and my middle finger just happened to slip into her cunt.