Recently, we were fortunate enough to acquire several of the Large Folsom Electro-Catheters.  If you are looking for something to really stimulate the urethral canal, give one of these soft silicone inserts a try.  They are made for soft conductive silicone, which makes these Electro-Catheters extremely conductive.  These are the Large (1/4″) 6mm version.  Each insert is 6″ in length.

These are also, Single Pole electrodes, so you will need another electrode placed elsewhere to complete the circuit.  Banana sockets are embedded into the top durable plastic T housing for a good solid connection.

You don’t really have to insert these all the way to enjoy toe curling, electrifying results.