As a woman that felt exactly the way she does, I think you are heading down the right path… progressively larger, REALISTIC is key ( it’s a mental thing). Drinking helps for sure… this is all about trust (at least in our relationship). If she won’t drink specifically because she doesn’t trust your motives about talking dirty, then you are a fat ways off from seeing your wife with another man.
in my case… turns out that my husband was working (female) with one of his co-workers (he travels so first times with people you won’t see at the grocery store might help). And they said it was damn near 3 years before the timing was right for some wild moves… for us is was a trip to bikeweek in Myrtle… no kids, party vibe all week and hot rides making getting naked at the condo a necessity. It was my husband and I, his best friend and this girl who is now one of my best friends. Late one of those nights she just up and grabbed me and before I knew it I was eating pussy for the very first time! Not to mention that completely blocked the fact out of my head that my husband and his friend were sitting there watching in total surprise!!!
bottom line… it’s your wife… you gotta play the long game and be patient. For the right chemistry and mood to be spontaneous… it’ll take a lot of planning and effort on your part for her to feel like you didn’t just throw her into something. That’s my opinion anyway… for what it’s worth. Alcohol and trust work great together. Good luck