It is such a challenge - I wish I could just send him with any of the countless Gerber Graduates Advanced Cups with Cup-Like Rim.
Similar to this one but in different patterns and not all insulated:
http://www.amazon.com/Graduates-Teenage-Turtles-Insulated-9-Ounce/dp/B00H96PGKW/ref=sr_1_23?ie=UTF8&qid=1437101162&sr=8-23&keywords=gerber+sippy+cup
This thing does NOT leak - I can throw it in my purse with confidence - sideways, upside-down, still no leaks.
I have not had such luck with water bottles. My son really likes the 9 oz Lifefactory glass water bottles with silicone sleeves and flat screw on caps but I have had a horrible time with them leaking even after just weeks of use.
Anyone have any sucess with there Kindergartener using some other bottle with a screw tip lid sucessfully - like Klean Kanteens maybe?
Thanks.