How do you do that, do you guys like it?

Meh, I am impartial to face sitting. Can't say I like it but I'll definitely play along if it pleases her. I find that this position does not allot me a lot of control over the use of my hands and some women also tend to blur the line between face sitting and smothering! The latter isn't one of my fetishes so I'd rather live to see another day as enticing as death by sex may be.

I love it

I love oral, I love going down on a nice , clean, shaved lady. So for me , "yes:, I love it!
As far as you straddling his face, just put your pussy on his face. Don't overwhelm him, you know, let him be able to breathe. Make sure you are clean and ensure he is willing to lick you silly. Some men don't like it. You can try to have him lay down on his back while you suck him and turn and put your ass/pussy towards his face while you suck him. (69).
The more you are distracting him and he is enjoying it the more luckily your are going to get away with whatever you want to do to him or him to do to you.