We do a lot of swinging but never with anybody who is drunk. When we have a swing party, we all get together for lunch at a restaurant so we can get to know each other. Then we go to a nearby hotel room, get naked, and party for about three hours, until everyone is well sated. We do not have booze in the hotel room because we find that it dulls the sensations. The parties we used to go to where people were drinking were usually flat, as people sat around drinking instead of fucking.
Recommend that you watch some porn of MFMs, etc. Talk with her during the videos and during sex about having a guy join you two. We recommend getting started by going to a swing club, watching others, and then getting into the mix. If you do not have access to a swing club, go on-line with swing site, find some parties, or find someone who can join you for a trial run. The first time we went to a swing club we agreed only soft sex play, no penetration. We were both fascinated watching others and had soft sex play with two other couples. The second time we went to a swing club, we went in with the same ground rules, but after an hour we were playing with a compatible couple and we crossed the bridge. The guy was going down on my GF giving her orgasms, and I was doing the same for his GF. The guy was between her legs and sat back on his knees with his hard, condom covered cock in his hand. He asked my GF if he could have sex with her; she looked at me and raised her eyebrows as if to ask me; I shook my head, "Yes;" she reached up and pulled his shoulders toward her; and he slid his cock deep into her very wet pussy in one stroke. We have been swinging since.