Sometimes he hits, sometimes he misses, but he CONCENTRATES on it quite a lot, and he seems to enjoy the activity. Of course, water is spilled, but people, it's water! It can be cleaned up!
We ended the activity when he started really not concentrating, pouring outside the bounds of the project, etc. His actions told me he was finished with this fun for the time being. So, we cleaned up the water and put the stuff away. Then, we got it out another day, when he found it equally engaging. This time, we did it on the kitchen table, and when water spilled, LM took an active role in cleaning it up. Cleaning up the water, also an important skill, was just as interesting to him as pouring it between vessels.
I'm sure we'll do this again and again, as it's a hit!
See you soon!