Vibrators, specially those which are very life-like (veins and all!!) are a great way to introduce your wife to cuckolding you. When we first started fantasizing about her getting fucked by other guys I would tell my wife to pretend the vibrator was an ex-lover she was crazy about and to show me how he did it to her...she would go wild with the suggestion and really go to pumping herself good...I would whisper in her ear how beautiful she looked with that huge cock inside her sliding in and out. I would say the guy's name and ask her if he was making her feel good. Her orgarsms were tremendous!
Eventually we moved on to my wife taking on real bulls and letting me watch the action, and if the guy is willing, double teaming her. The sex is mind-blowing for both of us, and it all started with the purchase of a simple vibrator...don't under estimate the vibrator's power of suggestion! It is a great ice breaker! If you give him a name (the vibrator) it will make him seem more real...until the real thing comes along.