When we were in high school, a friend of mine used to get liquid nitrogen from his father, who was a chemist, and put it on his tongue and blow smoke out his mo

When we were in high school, a friend of mine used to get liquid nitrogen from his father, who was a chemist, and put it on his tongue and blow smoke out his mouth and nose. I thought he was nuts! That he would crack a tooth, or some such, but he never did. IIRC correctly, he stopped when he accidentally swallowed a TINY amount. I think it made him burp for a while, but other than that, he was apparently unharmed.