How often does your small being respond to a direction with "5 more minutes" or "in 5 minutes"?
How often do you agree to give them more time?
If you answered sometimes and sometimes, wonderful! If you answered rarely and rarely, great! If you answered always and always, let's talk...
When a small being is given a direction, such as it's time to leave the park or clean up the toys or come to the table for lunch, this should be a signal to listen and follow the direction. Occasionally allowing the small being to negotiate, in a polite way, is reasonable. Your small beings should be able to follow the direction if you say no to their request for more time, without problem behavior.
If you are finding problem behavior when giving directions, you may want to look at one of my rules to live by: Mean what you say and say what you mean. Here are 2 ideas to try. 1. Use specific choices rather than directions. Such as "Do you want to clean up now or in 5 minutes?" This will create a different dynamic than a direction, which requires a specific action. 2. Pick one time to say no to a request for more time. Pick the time when you know you have time and energy to follow through on saying no, even if undesirable behavior arrises. It is important for small beings to accept being told no.
Small beings thrive with structure and clear boundaries. They will push up against them and test them constantly. It is our job as the big beings to show them where the boundaries are by meaning what we say and saying what we mean.