I was having a one night stand the other day. We got drunk and consented to have sex. She tells me to choke her, so I did. I applied pressure to the sides of her neck but very gently. She instantly passes out in less than 2 seconds. I was extremely worried so I stopped having sex and tried to wake her up. She had no memory of passing out but continued to act the same as she did before passing out.

Is this a serious issue and should she speak to her doctor about this? It scared the shit out of me and I am not going to choke her again.