LO is 21 months. We just started implementing time outs not too long ago and I am a bit confused to how to consistently reinforce it. Hence the question: When do you call time out???

It all started when LO flipped his dinner plate over on his tray on purpose despite of how many times I told him not to (he did that repeatedly for a few nights). I got really upset, took him off of the high chair and sat him on a corner of the living room for less than a minute (actually more like a handful of seconds). He cried and cried the whole time. That was very effective. He never flipped his plate ever again since.

And to be honest, I am amazed how he would sit on a corner as told.

I have adopted the 1,2,3 approach too, where I'd start counting 1,2.. and by 3 he would go to the corner, or he would lose a privilege (eg. not getting his security blanket for sleep). Now if he doesn't listen, I'd tell him, don't make me start counting 1,2,3 and make you sit at a corner, he'd get scared and would do what I asked him to.

Today, we were at a store and we were getting ready to pay. LO was at the lego table. DH asked him to leave, he says no. He starts crying when DH attempted to carry him away. I went over and did the same thing when DH went to pay. After unsuccessfully carrying him halfway, I put him down, told him I'll count to 3, and if he doesn't listen by 3, he'd need to sit at the corner when we get back home. So ended up he continued to cry until 3, and i told him the consequence. Somehow he quieted down and walked out with us. IT was very odd. I did put him in the corner when we got home for maybe half a minute (or less). There was no fuss.

But the line gets blurred. When do you call time out? He is at the "NO NO NO NO" stage where he'd say no when we ask him to do something (eg. cleaning up, putting clothes in laundry basket, bath time, bed time...etc.) - Do you start counting / giving warning on all these occasions that he says no? I am not trying to make him not say no or not have his preference if you know what I mean. I don't want to over do it, but I don't know where to draw the line. I definitely do not want to do it everyday, he is a very good kid overall.

There were also 2 times recently he slapped my face hard (yikes, the hitting stage, my biggest fear). I said no sternly and explain to him why we don't do that, which I think he understood (?), and didn't give him a time out. Today he slapped me again with a small book when he was on the potty (he isn't potty trained yet, we are just playing). I can not tell if it was an accident or not, so I just told him no and reminded him that is not acceptable, but didn't give him a time out. I also didn't want to complicate the potty time as who knows, he may hate potty time afterwards.

Advices please!!!