Well, he didn't get pinned hard, but it doesn't make him any less of a Lance Corporal. =D
One of the many amusing/painful traditions in the Marine Corps is the "pinning" ceremony: when an enlisted gets promoted, the person giving the chevrons pins them onto the enlisted's lapels, but doesn't put the backs on them (they're
straight-backed), he's then allowed to hit the pins as hard as he wants (yes they can draw blood) and, for the rest of the day, the Marine has to leave the backs off the pins and anyone of a higher rank can hit them.
When I visited EJ awhile back, one of his buddy's had just gotten promoted to PFC, so the backs of his pins were off. EJ, totally relishing the opportunity, gleefuly pounded his fists, and the pins, into the poor guy's chest. To his credit, the PFC didn't even flinch as he pried them back out (apparently, earlier in the day someone had struck a vein, which bled through this person's cammies).
EDIT: It's a matter of pride not to flinch when someone pins you. I kept freaking out at the prospect when I was down there in Florida and the guys around me just kept repeating, "It's no big deal."