A Special Taxi Moment

Today, I get in a taxi, outside of our apartment to go to the closest subway station. We drive about 5 minutes, if that, and the taxi drivers tells me in Chinese "wait a moment" as he pulls the car over to the side of the road and hops out. I am wondering "what in the world?!" at first thinking he got pulled over by a cop (which has also happened to me in a taxi here) - then as I whip my head around following him - he goes to the side of the street and zips down his pants - at that point I figure out what he's doing and go back to checking messages on my phone. He quickly hops back in the car and off we go. The things that make me go...hmmm...