If you do "sounding" then a catheter shouldn't be a big deal. Your urethra won't know the difference, just make sure anything you put down your pee hole is sterile. Have fun!
Shod full your bladder up with blue Dawn dish soap it the best another favorite is toothpaste hot 2 hold tube of extra strength mint toothpaste in my bladder now with catheter plug tight been inside my bladder for 2 hours now got pee so bad pooped ton trying to pee told not to poop so got inflatable butt plug enema lube up with toothpaste and put in and pump up huge plug enema tube huck to 2 gallons of very soapy water click open flow fast inside my bum