Used in informal settings among friends or casual conversations, not in formal situations. While waiting for the movie, we fiddled around with some games on my phone.
Pro Tip 2/3
No Progress
Implies a lack of progress or direction in the activity being done. I fiddled around with the code, but couldn't make the program work.
Pro Tip 3/3
Killing Time
Suggests a way to pass time when one is bored or waiting for something. To kill time at the airport, I just fiddled around on my laptop.