Can you circumcise yourself?

My boyfriend ALWAYS claims that when he was little, he was originally uncircumcised but was one time playing with it (I think he said he was 2-4) and pulled it back to far and the skin just fell off?!

I’ve never heard of this and couldn’t find anything online. I’m not sure why he would be lying about this, and he genuinely seems to be telling the truth, but is that even possible? 😂