Our 4-year old son is unpacifiable when it comes to saying bye-bye to his friends after playing. He would cry like anything and doesn't mind lying on the street, adamantly not wanting to part with his friends.
What could we do about this?
Is there any way to give him some control over the leave-taking? I'm thinking of something like what we do with daycare and night-times (kids push us out of the room), that he could do when it's time to leave the playdate. Maybe have a kiss/hug be the bye-bye signal? Or maybe you could tell him, "Okay, hon, in 5 minutes we will give a hug to our friends and then you are in charge of unlocking the car/opening the door/picking out the snacks for the ride home/choose your own adventure."
Immediately, off the bat, I recommend to never, ever give in to this type of behavior. Also make it clear that it is unacceptable. When he begins to whine, cry, and throw a fit, there should be no more "Ok, just 5 more minutes". This only helps to encourage the behavior. You need to control the situation and by doing that you take a little less control away from yourself.
What was typically done with me, and what I am beginning to do with my daughter is to give her advance notice of what is going to happen. We give her warnings. We involve her in the cleanup process (putting toys away, wiping off tables) and then we begin a long string of good byes. By the time the clock ticks to when we have to leave, she is already separated from the activity and is ready to go.
When she gets older, I will add a further step before we even begin to play by letting her know what time we will be leaving rather than leaving it open-ended. However, since she has no concept of numerical time right now, that step can wait.
For any sort of leaving, I find that timers are highly effective. Whether an egg timer, or a timer on your smartphone or watch, having something that creates an audible sound after time is up is very effective for setting time-based boundaries.
For example, you might tell your son, "Johnny, you have five more minutes until we have to go home. I'm setting the timer for five minutes." Then do so. When it goes off, remind him that the timer has gone off, and tell him to start packing up immediately - and enforce it, with time outs or whatever your normal discipline is, strictly.
This worked really well after the first couple of times with our 2.5 year old, and our daycare uses it with all ages and finds that it works wonders. He now often moves directly to do whatever he's supposed to when the timer goes off without me saying a word, just from hearing the beep from my phone.
Is it that he doesn't want to leave his friends or he doesn't want to leave his friends having fun? SOMETIMES if you are at the playground and need to leave, the other parents need to leave soon, too. If that is true, ask if you can ALL tell your children, its time to go in five minutes. Or if you are at their house, tell your kids that the other kids are going to have to take a bath/have supper/clean their rooms now anyway, so the fun is going to stop. Also, I used to tell mine that we can't come back for a play date unless we leave this one without any problems.
Or maybe you can say "We need to go home now, and when we get home you can draw a picture of you and your friends having fun."