I understand that managing bedtime routines with a child who has ADHD can be challenging. It's important to approach the situation with patience and understanding. Here's what you can say to your 10-year-old:

"Hey, $Child's Name$, I know how much you enjoy your bath time, and it's great to see you having fun. It's getting late now, and we need to start winding down for bedtime. I understand that transitions can be tough sometimes, so let's find a way to make it easier. How about we set a timer together? You can have a few more minutes to enjoy your bath, and when the timer goes off, it'll be time to get out and move on to the next part of our routine. We can even create a visual schedule that helps us keep track of the time. What do you think?"

By acknowledging your child's enjoyment of the bath and involving them in finding a solution, you show empathy and give them some control over the situation. Setting a timer and using a visual schedule can provide structure and help your child understand the transition from bath time to bedtime. Remember to use a calm and reassuring tone when discussing this with your child.