Here's how Alison got her little guy to tip his head back during shower shampoo rinses:
Whenever I rinsed the shampoo out of my 4 year-old's hair he would curl his chin down to his chest making all the soapy water run down his face and into his eyes. To get him to tilt his head back I drew a tiny sailboat on the ceiling in eyeliner and told him to look at it while I rinsed. Not one drop went on his face!
Eyeliner! Impressive, Alison! A sticker would work as well as long as it could handle the steamy conditions in the bathroom. Another option: an X with electrical tape!
More: Tips for bath time