as in "You can get a BONer from even mediocre porn."
Let's call the single dot inside the diaper a tiny turd. OK? Great. Aaaand, all together now,:
A mediocre man walks around with a diaper with merely a single turd in it.
commonplace, ordinary, mediocre (i.e. rapping about rims)
an ordinary person, a common mediocre person.
I'm like a little mediocre DOT on the internet, telling jokes about GEORGE MICHAEL'S MOUSTACHE.