I don't have any kids so I have to hit other peoples kids.
My ex-gf has a 6-yo girl. She is great fun but can be very cheeky and obstinate and naughty.
They come and stay sometimes and one time I was showing her the pool water chemicals changing colour in the test tube and she smacked it out of my hand with no warning. I just smacked her on the arse where she was standing and told her not to be stupid. She took it quite well and did not cry. I think she was just testing me.
I am not sure if I passed or failed.