For anyone curious like I was, Dicking Around is not what i thought. Looked it up and...
"the phrase "dick around" is actually from "dicker around" which is a 19th c. term. "Dicker" is to "Engage in petty argument or bargaining" and "Treat something casually or irresponsibly; toy with something". So when someone is "dick[er]ing around" they are treating serious matters lightly or doing things in an unnecessarily protracted way; which is precisely how we use it.
The word "dick" however, which I would gather, people would envision it meaning "penis" here, simply doesn't work. We don't use "dick" as a verb, yet alone a progressive verb. "To dick" or "to be dicking" a person, although fairly clear in its sexual connotation, is certainly not in use, "dicking (with) a person" however, makes perfect sense, because it's from that ye olden term "dicker" again.
So "dicking around" has nothing to do with the slang term for penis or the disused colloquial meaning of a rookie detective, or it being an everyman"