As you unzip you notice your friend Dennis walking in and moving to the urinal next to you. You both start to pee, eyes glued to the wall in front of you, keeping quiet.
Your dick begins to thicken and lengthen in your hand, but you keep your eyes ahead. Its almost as if you are getting hard, but you're not. If you had looked down you would have seen your cock getting darker in color, a foreskin starting to form.
As the foreskin encompasses your large chocolate colored cock head your stream becomes erratic, missing the urinal. You quickly stop your stream, looking to see what the issue was. Your jaw drops as you see the thick uncut black meat hanging from your crotch.
"Dude, watch where your aiming!" Dennis said as you almost sprayed him as he looked toward you. His eyes caught a dark mass in the base of his vision and all it took was a glance before he was fully staring. "What the fuck dude? Why is your cock black..."
You go to look up but your eyes catch his own member in his hand, pale white, cut, smaller; YOUR DICK!
"Hell if I wouldn't know any better..." Dennis started as he looked down at his own cock, "HOLY SHIT, give me back my dick!"
You both stand in shock, staring at each other's and your own new members.