Brushing Teeth Obsession

Alisa has become obsessed with brushing her teeth these past few days. She wants to do it by herself all throughout the day (just with water though--no toothpaste, which she still just sucks off the brush as she brushes). She is actually brushing really well each time, not just playing around. Afterwards she will fill her Hello Kitty cup that we keep in the bathroom for her and drink and drink and drink water. Sometimes she starts to make a mess by sticking her hands in the cup to wash them and then her face. So far she hasn't knocked the cup over. I'm glad she likes to be clean, but sometimes it's a hassle when she goes to do all that in the bathroom because her shirt usually ends up wet (sometimes really wet). A few times I actually told her no when she asked if she could brush her teeth because I knew that meant she'd most likely want to play with the water too.