I got this idea from our devotional book 🙂
You overfill a plastic cup then sit a piece of cardboard on top of it and flip it over. Make sure to have a towel down and a container to catch the mess 🙂
The cardboard will stay on the cup upside down because the water is holding on to it.
I am not sure how long it will hold because Little Man just wanted to squeeze the cup and splash the water 🙂 That is fun too!!