When it comes to wasting time or being unproductive, "diddling around" is a phrase that comes to mind. But there are many other synonyms to describe this type of behavior. "Lollygagging," "frittering," and "loafing" are some of the most common options. "Dawdling," "wasting time," and "procrastinating" are also good choices. If you want to take a more positive spin on this type of activity, you could use words like "exploring," "experimenting," or "playing around." Ultimately, the words you choose will depend on the context and the tone you want to convey.