I wouldn't worry about it too much........it's actually quite an experience - hehe - something that just adds to the experience of wearing your dress....hehe
But seriously, don't go starting to take something on the day, in the 'hope' that it will stop you going to the toilet. That could lead to disastorous effects that you don't need on your wedding day. Approach it as just something quirky that you and your DH or bridesmaid or mum can help you with
I was pretty much right after the 1st time, I had it down pat as to how I would "set myself up" so that I didn't need anybody's help.....hahaha......that sounds strange.......
But seriously I don't think you should worry about it........it's just all part of the day!