As a father of a four year old, there are nights that I would wake him around one or two in the morning to take him to use the toilet to prevent him from wetting the bed. Usually one of three would happen:
1 - He would go right away.
2 - He would say he doesn't have to go but ends up going anyway.
3 - He would say he doesn't have to go and I'd leave him in bed depending on what he drank throughout the day.
I can't say if this was your mom's intention with you or not, since you did not provide an age range for when this happened. As for touching you, you did tell her not to and gave an excellent reason why and she ignored that reason. I would consider this to be a form of sexual abuse. Overall, I am very sorry you experienced this.