I have a female friend that passes out quite regularly. This is accomplished by oral sex and rolling her nipples between My fingers. she has passed out completely in excess of 10 times per session on numerous occassions. I believe her passing out is caused by endorphin overload to the brain as opposed to hyerventilaint. Once she passes out the first time, the following ones come rather easily. She can not masturbate, or has no success at this. but on many occassions once she passes the first one almost anyting will cause the following ones to ensue.
Oh, do ask Me about the time she had a little to much to drink, she was out cold, if not farther, in excess of 30 minutes. her body became cold, her eyes rolled back in her head, she was not breathing. I can only suggest you do not leave her unattended once she does pass out, monitor her conditions closely. I fought for 30 minutes doing CPR to get her back, and even dialed 911 before she came to.