The ONLY method I've found works for me in active situations (concerts mostly..complete with "mosh pits") is pocket carry of a small gun.
My p-64 slips into my pocket and thats all she wrote...unless someone literally feels me up there's no way to tell I'm carrying.
"...with liberty and justice for all." (Must be 21. Void where prohibited. Some restrictions may apply. Not available in all states.)