A mild slang name for a
penis, supposedly less offensive that cock, prick, or dick, it does not have the fecal connotations of
dingleberry but is used to describe the
penis in much the same circumstances by much the same people. In addition it can also be used as a mildly disparaging term for a person who has exasperated you by doing something atypically stupid.
"I had to rush like hell to get here on
time. I was halfway here when I remembered I'd left the
contract in my desk at home and had to go back for them, I
felt like a right dooberry."