Steve and others having problem with climacturia (urine leakage).
Following my prostatectomy 12 years ago my catheter had to remain in place for over 5 weeks. When it was removed it felt as though a tap was fully turned on! I had no help from anyone. Things were so bad that I used to just sit on the toilet for long periods to get some relief. Then a couple of days after the removal of the catheter, while sitting on the toilet, I instinctively tried to stop the flow. Guess what I could feel the rate of drips slowed a little. That was a Eureka moment for me and from that point onwards I would sit on the toilet, squeeze to try and stop the flow for the count of ten, then let go to the count of ten, repeating the process ten times, three times, a day. After a week or so I felt I was making real progress and continued for about a month and gradually reduced the number of pads - eventually to a single pad per day and that is where I am even now. I always put a small pad in my underpants for safety.
In my opinion I really would not let anyone 'put a finger up your bum', as you say. The point where the urethra is attached to the the bladder is vulnerable to damage and you certainly don't want to go there! You have to let the healing takes place for a long period before interfering with that part of your anatomy!
I know there are physios who will train you to locate your pelvic (Kegel) muscles. Every time you go for a pee you are using your pelvic muscles and if you were to interrupt the flow you are again using the relevant muscles. I really don't think you need anyone to teach you how to train your waterworks to return to normal. Those who have just had a surgery and leaking why not try this intuitive technique, you have nothing to lose! Let your body naturally heal itself with a little help.