fiddle around
(with someone) and fiddle about (with someone) to tease, annoy, or play with someone; to waste someone's time. All right, stop fiddling around with me and tell me how much you will give me for my car. Now it's time for all of you to quit fiddling around and get to work. Tom, you have to stop spending your time fiddling about with your friends. It's time to get serious with your studies.
fiddle around (with something)
and fiddle about (with something)to play with something; to tinker with something ineptly. My brother is outside fiddling around with his car engine. He should stop fiddling around and go out and get a job.