I personally don't understand people and the kink for *Sharing*
Like its their thing they like sure but really... At that point of liking sharing why not just find a Woman of the evening then and share her.....
Well, it's not really that hard, actually. One main reason, as stated above, is that everything is better when you share it with your friends (a game, a meal, an experience).
Another main reason is that some people get really turned on when she (the girl) is more excited. And in these people's minds, two tongues lick better than one, and so on.
I myself get incredibly turned on when my wife is turned on—the more aroused she is, the more I am. So personally, I find the idea of sharing her really arousing for me.