What is the man from Nantucket?

It is something that is NOT to be told in mixed company! Here it is:

There once was a man from NantucketWho kept all his cash in a bucket.But his daughter, named Nan,Ran away with a manAnd as for the bucket, Nantucket.
There once was a man from Nantucket.
With a {private part} so long he could suck it.
He walked down the street,
Just a swinging his meat
While carrying his balls in a bucket