Your best friend went off and enlisted, while you went away to college.  On leave he came home with two of his marine buddies.  You could not believe how he had changed.  He was now lean and muscular, covered with tats and much more sure of himself.  You complimented him on how much he had grown, becoming a real man.  He looked at you, laughed, and said that you had not changed a bit. 

He just sat there, shirtless, and smirked at you, pulling his thick meat out of his khaki boxers. You could not tear your eyes away from your best friends transformed body and dick.  He kept looking back at you, slowly stroking his cock, while his two marine buddies took turns raping your ass.