The thing about swinger parties/clubs is that some of the guys at the party, especially if they're there as singles, know they can fuck, are confident in their abilities, and can sniff out the less capable and confident men instinctively and will focus on their wives. The wives recognize and are attracted to their confidence.
So even at a swing club or party a real Bull will sniff you out and next thing you know He's fucking your wife in front of the whole party as you hold His drink.