If it doesn't hurt, then it's propbably nothing more the air getting trapped in your wrist's as you turn it. Some Ortho guys say it's air trapped in a certain joint. Like when doing squats and you hear popping noises. It doesn't hurt but sounds weird right? Yep! Sometimes something gets caught in between the joint surfaces. Unless it's a early sign of arthritis, but I cinderly doubt this. Arthritis can lead to popping sounds in joints. A torn cartilage in the knee or a loose piece of bone or cartilage in the joint can do this also. But it doesn't sound like that cause you didn't mention any old injuries.
I have a 9 year old indian female client (future gymnastics) and every time she does anything in a squatting position you hear sounds like pop corn popping in her knees. She has been checked time and time again. Nothing wrong with her knees. Cleared by Ortho, Endo, Neuro. They said it's just her knees making noises for now.