I want to see my wife used

Alright so I’ve always had this fantasy of my wife with a BBC we’ve even role played in the bedroom but I can’t convince her to do it for real I know she likes big cock because she uses a 9 inch dildoe so it’s not that she’s scared of size, and she not afraid to have sex in front of me either she has already done that with my buddy btw that was hot as hell!! So my question is does anyone have any tips that I could use to sway her to doing it?