We've had the tantrums, dgs is about to turn four and will now and again still 'try it on'. His sister is 7 and is a very well behaved child, even when naughty it is more just like mischief. But she too had her moments.
The naughty step worked really well for us. We absolutely followed the lead of our DS and DIL who are very firm over tantrums/meltdown. At the first sign of unacceptable behaviour they get a warning. If it continues they are told - 5-4-3-2-1. This is now enough usually enough to stop whatever is going on. If we get to 1 they go on the naughty step.
If they try it a third time it's straight onto the naughty step which is actually the third tread on the staircase.
When out for dinner they are allowed to get underneath the table and 'play' etc. But at food time it's up to the table and reasonable manners are expected. If one of them plays up they get the 5-4-3-2-1. If they continue to play up then (usually) Daddy takes the hand of the child (it's usually the 4 year old) and they go outside to diffuse the situation and so not spoil the meal for any other diners. DGS calms down eventually, it may have been over eager enthusiasm that got out of hand or it may have been naughtiness, and when he settles, and understands why he was removed from the table, he comes back and says sorry.
Mind you, he might try it on again But that would usually result in no cartoon before bed, or no favourite toy to bed.
Last week the two DGC were bickering unrelentlessy. They eventually lost privileges of their i-pads for 5 days. Lost of priviliges is exactly that. There is no giving in by the parents.
Now, DGS can do absolute meltdowns with the best of them. He can be very defiant, and can on occasion kick, throw, the full works. etc.
I think that the reason the naughty step works for us is because right from the very beginning when it was brought into being, it was adhered to without any parent/grandparent giving in. Tears/shouts/screams/drumming heels/snot while on the step....... All of us ignored it. Then whoever put him on the step goes and has a little chat, are you now calm, do you understand why you were put on the step, what do you say (sorry), it has to be a real sorry or parent walks away and he is still on the step. He soon says a real sorry.
Sorry for the long post, just wanted to say that we thought DGS nearly 4 years would never respond to the naughty step. It only took a few goes until he got the message and understood that we don't give in.
OP - when the naughty step was tried was the method of carrying it out consistent, over and over and over again. It can be hard to keep on at it but for us it paid off and generally, we can take him anywhere and expect decent behaviour.
I'm your your DGS really is a delightful child who is just pushing the boundaries and seeing how far he can get.
The adult is in charge.
If DGS comes to you for a few days have a great time.
I agree, definitely no 'sending away' or 'won't love you any more'.
We've used the phrase, '''That was very naughty and it made me very sad'''
Good luck.
Sorry again about the length of this.