Ive had sleep paralysis for many years. For me it comes on more when Im extremely tired or stressed, but it's probably different for everyone. I was horrified when it first started in my teens, I couldnt move and felt like my chest was really heavy, and sometimes hallucinations.
Ive learnt to deal with it and am not as scared of it anymore, I can sometimes tell if it's going to happen(usually when im over tired) and sleep on my side. The main thing you can do is sleep on your side. Sleep with your blankets tucked in around you if your concerned, but I havent heard of anyone suffocating from this.
I just lay there and try to relax when it happens, knowing what it is and that it cant really hurt me, I use my mind to jolt my body out of it. Its hard to explain. It is a condition and you should speak to a sleep specialist/doctor if your really worried. They can give you tips on how to handle it.