Those who have done it - what do you find hot about couple swapping? How do you know if you’re ready to try it?

We first got into it primarily because the GF and I wanted to view how each of us looked while fucking. Yeah you can film yourself but it is a real thrill for me to see a cock pounding her. She really likes watching me do missionary from behind. She gets so wet just watching my cock go in and out of another woman's pussy