I have a rule. You aren't allowed to tip your chair back and balance on 2 legs until you have a job and can buy me a new one if you break it. For those wondering why this rule is so complicated (instead of a simple "keep all chair legs on the floor" rule), it's because Cr likes to tip his chair back sometimes.
The consequence for breaking this rule is that you lose your chair and have to stand until further notice.
Last night Z was the first to lose his chair at dinner. Then it was L.
Mommy: L, don't tip your chair back. You've lost it.
L (with a smile): Oh, I can't stand it.