Port o' Jawn is just another word for
Potty queen,
Potty King,
Port o' potty & porttipotties.

Port o' kabin

and so on.
Port o' jawn is used by people mainly from Philadelphia.
Hence the word jawn
(:
I have to go take a dump in that port o' jawn.
Yo' there anymore port o' jawn's left?
Any port o' jawns 'round here?
by Kieferx3 January 17, 2010
Get the Port o' Jawn mug.