Dear OP! Please look at this video! This girl gone really very far, I think she almost died. I haven't ever seen someone gone so deep!. And, dear OP, look at her eyes, it is awesome! It seems that she goes, but suddenly she makes her eyes wide open! And then she finally goes.. Looks like she saw something, that we don't see, maybe her death!
It is something what I guess could inspire you and help if you want to perform the asphyxiation death.
hxxp - motherless.com/g/real_breath_play/3117D92
Thank you for that you doing, and.. we are waiting for new awesome works!