My oldest son is 3.5 years old. Before I took this class, we did a variation of the Uh Oh Song for when he had temper tantrums where I'd just put him in his room, but get him after a few minutes and ask him to calm down before he could come out. Basically, I would then help him calm down by holding him, etc.
So a few days ago, I decided to apply what we learned in class about the Uh Oh Song and followed the steps, specifically leaving him in his room until he calmed down on his own. Well, he screamed and screamed on and off for 1 hour and 15 minutes!! It was agonizing listening to him and so many thoughts were going through my mind. But I stuck with it and followed through with the 3-minute timer after he had calmed and then invited him to come out. He was like a new kid, super grateful to be out and so helpful with such a great attitude afterwards.
I can imagine that the key to this technique is being super consistent so that he really learns that the quicker he calms down, the sooner he can come out. I'm looking forward to it hopefully taking less time next time. I keep thinking about that example you shared about these investments we make now during parenting (even though they can be heart-breaking and challenging) will really pay off later.
Hats off! Once your child sees you being consistent, time and time, even if it takes an hour or more the first time or two, things will go MUCH smoother in the long run.