CM,
May I ask if you have a problem with your urethra in addition to your BC, and is that why you're asking about a numbing treatment for cathing yourself? Because as far as I know a person doesn't usually use anything to numb the area prior to catheterizing, of course when a person has a cystoscopy they (the urologist) frequently use some sort of anesthetic as the scope is usually quite large compared to when a person is catheterized. I suppose if you were male that might be another issue, one I couldn't relate to since I'm female.
The best place to get this information however would be your surgeon's office staff or the surgeon, or perhaps your primary physician if you're more comfortable asking him/her. Perhaps if you shared a little more about your situation there might be someone who could relate and then give you their take on your questions.
Lou