Cleaning Help?

So I'm getting the hang of getting my mom to the toilet when she usually doesn't have to go. After she tries, I have her stand up so I can use the wipes. She has clean pullups and her pants in place. And shoes, So I just need to wipe and pull everything up...but then when she stands up, she starts to pee and every thing's ruined. We're back at square 1. We can repeat this process a couple of times before I just give up and let her go a little bit soiled. Is there a trick to catch the urine that is just waiting to escape as soon as she stands up. Thank you for any tips you may have!