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1.
Dry humping with your clothes on.
So did you get laid last night? No, just some jean jamming. Man, my dick is chafed!
by jrjohnson78 April 19, 2006
 
2.
Dry humping with jeans on. Often causes irritation and chafing.
Justin Timberlake at 2011 Spike Guys' Choice Awards: "are we going to spend 2 straight hours jean jamming them until chafing occurs and we have to walk all funny for 3 hard days?"
by 51westside July 08, 2011