Back in the day, say 40-50, maybe even 35 years ago, some swingers parties included canine activities. Emphasis on SOME. Usually those were in the more hedonistic locales involving a group that was well-known to each other and where doing zoo had been brought up earlier, not just sprung on participants.
The video Atlanta Dog Show is a good example of such a party and the dear, departed old Yahoo group Lake of the Ozarks Knot Riders was devoted to the goings on at their events. Some good videos from those parties in their group page.
All long gone, sadly. The anti-zoo crackdown came and Yahoo erased close to 400 zoo groups that I knew of at the time. And zoo has been driven more and more into the dark over the past 30 years.