G: gag
Sometimes your hotwife/hothusband and their lover just want to make love without being distracted by you. And, you both know it can be hard for you to keep silent when you're watching such a hot scene. You love to comment on how hot they are together and how much you enjoy watching your partner experience the sexual ecstasy that you were never able to give them. That's hot but can be distracting or even annoying.
Of course, they could just as easily kick you out of the room or even out of the house to get the peace and quiet they deserve, but a gag can work just as well. This way you can watch without disturbing them. The gag really is a gift to you. After all, it's this or you don't get to watch -- or even listen -- at all...