Panning photography is simply moving the camera while taking a picture. It’s often used to capture objects in motion such that the object is in focus while the surrounding is in motion. It’s especially hard because the lens needs to travel at the same speed as the object. The resulting effect is the moving object appears stationary relative to the camera lens. Additionally, you may care about the path that the camera moves through because that may affect the blur lines in the background. In order to achieve more motion blur for the background, you also need to set the camera exposure time to 1/20 of a second of more.
Crew is perhaps the best practice target for panning photography if not NYC taxi cabs. More than 200 shots later, I got these two that I like. One focused on the rowers and the other on an oar. The success rate is very low, practically random, depending on luck. This makes taking panning pictures of people, like your friends, especially hard. I would take a bunch shots on people that I didn’t know for practice and still manage to screw up on the ones of people that I do know. Sports or dance photography is challenging that way. A moment passed is missed forever; you can’t recreate it nor does it wait for you.