69 is too confusing to do for long!

I like her to put a doubled pillow or similar behind the back of my head; that way my face is at about the right angle when she's kneeling upright. She can then rest her elbows on the bed head rest and move her hips around how ever she feels. Us poor men soon figure out how to breathe through the corners of our mouths so don't worry about that - just don't sit back on his jaw with all your weight in case you dislocate it!

Facing the other direction is also good - still use the pillow to lift the face up. but now you have to support your weight on your arms - more tiring I believe. I don't actually know because I'm just down below stoking the fire.