Purposely tipping the kayak to practice wet exits is hard to do. Huge mental block about leaning over until you flip upside down in the cold water.
Accidentally tipping after you've chickened out and returned to the shallows to fool around with some J-leans and lean turns: remarkably easy.
Unfortunately, if you're leaning back when you flip, you will bash your face on the sand when you reach forward to pull the release on your spray skirt. And then, when you panic because you're under water and just bashed your nose so you kick upwards to push the kayak off, you'll end up with brilliant deep bruises on your legs.
Ask me how I know.