There have been a few topics about this subject. Although it's sexy, I've certainly done it and had it done to me, it's exceptionally dangerous. People have been jailed for accidentally killing their sexual partner.
Even the high level kinksters tend to shy away from it. This is the best essay that I've read, by Jay Wiseman, about choking and his thoughts on it from the perspective of once being an EMT and now, an attorney. It's really good reading:
http://www.jaywiseman.com/SEX_BDSM_B...irst_Essay.php
I'll try to find the other topics for you to peruse. Just remember, it's in those moments of hot passion that a partner wants something. But a man's hands are VERY strong and if you don't know about pressure points, etc., someone could be seriously injured.
I, personally, believe that it shows good sense to have stopped when you did after she begged for more.
Elisabeth
P.S. Seemed like a hot time!
Edited to add:
http://www.jaywiseman.com/SEX_BDSM_BreathPlayMain.php This is the most recent of articles concerning breath play with links. Very good source of information.