Your friend has just been transformed into a six foot tall walking dick. Fortunately for you, no one seems to notice. There aren't that many people at the rest stop and the few that are there are either too drunk or too preoccupied to notice. But you can't take your eyes off of your friend. The same way that people are transfixed to stare at a burning building, you are transfixed to stare at your transformed friend.
Keith waddles back into the rest stop. When he steps inside, you can no longer see him and for a moment, the transfixion is broken and you can think. You have to do something to fix your friend. You have to try transforming him again. It's worth the risk because the worst case scenarios you can think of aren't that bad compared to leaving your friend as a walking dick. You get out of your car and follow your friend into the rest stop.
When you step inside, you are transfixed again. Keith is standing at a urinal with his head bent. From the slit which is Keith's mouth, a huge stream of urine is shooting at the urinal. You have never seen any spray that large. It's more than ten times more urine than normal. The urinal cannot handle it despite being one of the larger urinals. The excess urine is overflowing the urinal and flooding across the floor getting Keith's balls (legs) soaked in the process. Fortunately for you, the floor drains are keeping the urine away from your shoes but barely. You stay standing near the door because it's the only dry place.
Keith keeps peeing probably because once a guy starts, it is nearly impossible to stop until he's nearly empty. When he does finally stop, he curses "Damn these urinals. Something is wrong with them. I tried all three and each one spilled. Now my feet are wet. Would you go get me a towel please?"
Your thoughts about transforming Keith again are put on hold and you run grab a towel for your friend. You have to dig a little to find a towel big enough. You run back Keith is at the door of the rest stop.
"Put it on the ground and I'll step onto it."
You lay the large towel flat and watch as Keith places one testicle and then the other onto the towel and he starts wiping his feet. Then you realize that you have absentmindedly placed your arm around his shoulders but you realize he doesn't have shoulders. You're standing there holding a six foot tall dick. He turns his glans toward you and with his piss slit says, "Thank you for steadying me." You are face to face with your friends glans which is now bigger than your head. His foreskin is partially retracted and acting like a hood around his face. You smell a strong dose of pheromones on his breath.