Homelander
Male
First of all, that she is willing, it's not a moral speech, I'm serious, she can look at him, but would she really? If she would, then get closer to him.
Try to meet him for a beer, don't make a big deal of it, first joke about him looking at her ass, but make it clear that you don't mind, let him loose, If he responds well, tell him that you and she have a "liberal relationship", saying "I'm a cuck" scares many, tell him that you could make it possible, making it clear that there will be total discretion, it shouldn't be too difficult from there.
Try to meet him for a beer, don't make a big deal of it, first joke about him looking at her ass, but make it clear that you don't mind, let him loose, If he responds well, tell him that you and she have a "liberal relationship", saying "I'm a cuck" scares many, tell him that you could make it possible, making it clear that there will be total discretion, it shouldn't be too difficult from there.