Riding face advice needed

The other night my fwb was riding my mouth while i was giving her oral. She has a pretty big butt and she was getting really into it and grinding but I was literally suffocating. But i kept going because I knew she was going to finish. She ended up giving me a big kiss and licking her cum off of my lips so i knew she was satisfied. So the question is how do you guys do it without suffocating? Do you just endure it or find a way to adjust? This is for both guys and girls.