newbie has found a problem

Newbie here since July 2013. Last night I discovered a possible problem. My full face mask was leaking and after a few attempts at adjusting the straps I decided to just apply light pressure to seal the mask and get back.to sleep. I was on my right side with my arm underneath my head so I just put my hand on the top of the mask and gently pressed. The leak stopped and I fell into a deep sleep. Soon I was disturbed by my increased resp rate and a strange odor. I finally shook myself and was wide awake wondering what was happening. My mask was not leaking, however, and here is the dangerous part, my forearm was totally covering the vent! I was rebreathing my own air and the CO2 was building up. I was suffocating! The smell wax my own stale breath mixed with a high concentration of CO2!

Perhaps this has been discussed before but a search for "suffocating" didn't find the topic. Please spread the word to fellow users. If I had been drinking or otherwise not aware of what was happening I might not be here typing this!

Depending on your brand of mask, you may want to look for one that is not so easy to block,
or use a pillow with cut-outs for the mask.