Maybe he picked (selected) a peck of peppers that had been picked (removed from the plant)
Peter Piper picked a peck of pickled peppers.A peck of pickled peppers Peter Piper picked.If Peter Piper picked a peck of pickled peppers,Where's the peck of pickled peppers that Peter Piper picked?
He picked them, and yet they are not in sight. What can this paradox mean? The solution is that he has stuffed the peppers into his ass for his anal pleasure. Right up the pickle pipe.
If you were to stumble upon the words, you might perchance say what Peter Piper is thinking about. Even his name is pretty much Penis Anuser.
Peter Piper pricked a pick of peppy peckers.
(Edited 4 minutes later.)