My ex wife was well shared and mostly into younger guys. Every encounter was different but, if we ever ended up on the edge of the bed or couch with him eating her pussy, I would slide in behind her holding her, squeezing her big tits and watching over her shoulder. When she had enough licking, she would have him stand and I would guide his cock into her. I'd hold her tits for him to suck, rub her clit, squeeze her pussy around his cock as he fucked her. She also had really long lips, I enjoyed streching those wide for a better view and if she squirted, it made for a great show. We always made it clear to the guys up front that if they were afraid of another man touching their dick, they probably shouldn't come over.