fucking around
Not at all engaged in nothing productive. Though it may appear to an observer that the subject is doing nothing or thinly disguising his or her apparent idleness with misleading activity, the subject may be more open to the discovery of something new than if he/she was not fucking around. 
Hence, fucking around may be a modest term for continuous searching, remaining open to any and all fresh input. 
Fucking around may be experimentation in its noblest form. 
"What are you doing?" (asked while doodling on the guitar)
"Oh, just fucking around." By such fucking around there may be a sudden new melody that comes to the one who doodles on the guitar. 