Not sure about teaching them, but I did install cups for worms and it works perfectly. I just put the cups on the side of the cage just below where all my Chams bask so they can see into them. It has worked great from day one! One Cham goes over and looks into the cup everyday at a certain time to check for food, guess he has gotten used to his afternoon snack-haha Crickets I just toss in, chasing crickets is their exercise...
Then again, I have a Cham that drinks out of the catch bowl on the bottom of the cage under the dripper. I've had to control his dripping cause of it, poop falls in sometimes. But he still goes down into the bowl everyday to look for water... But this Cham is special(SPECIAL), one of the weirdest personalities I have ever seen!