The first time I ever heard of this was a couple of years ago by my son's counselor/social worker! She was telling me that she knew that a lot of people used belts to spank their kids and she had to keep reporting them to CPS for leaving marks. She told me that she recommends that people should use glue sticks instead!
I told her that I don't need that kind of advice and that I don't spank my kids at all. I asked her why she didn't just recommend that parents not spank and she said that it's so ingrained in people that they wouldn't listen to her.
Anyway, I am a very curious person- I decided to try this, (on myself- of course!! lol) but I didn't realize that glue sticks could be 10 inches long. I just grabbed a 4 inch one and flicked my leg a few times with it. Umm- that was dumb! I am very fair skinned too. But I had to explain my red marks to my dh- LOL. But I didn't do it hard and had red marks on my leg for at least 3 days- so I am not sure about this theory, but it sure made me sick that people would actually do this to children!