When you're fucking a girl, and decide to jam one of your arms all the way down her throat, and the other one all the way up her clitoris to the point where your hands link, and you break the girl in half.
The Chinese Fingertrap is not safe and should only be performed if the lady is consenting. Being the creator, I strongly suggest it be don't do it.
Oh man, bro, last night I was banging my girlfriend so she told me to Chinese Fingertrap her. I asked her if she was sure, so she said yes. I killed her, man!