The two of you still had your hands for now (all the better to grip their tails with), but they'd start going hoofy before too long. Getting deep and dirty with a horse girl tends to do that to you.
This bar had always had a heavy horse clientele, but that never bothered you and your buddy from work. It was the closest bar to the office, and the horse folks were personable, though boisterous and prone to loud, neighing laughs. The two of you eventually hit it off with these ladies, who seemed impressed at your willingness to intermingle...most people shied away from animal hybrids, especially with the risk of transforming. You shrugged it off. You all had similar interests, and they were hot as hell, besides.
So you ended up on a long series of double dates, the four of you having the time of your lives...until the fateful day when you'd all had one too many, and the two of them wouldn't stop whispering and giggling about some wild idea...their scandalous, taboo idea. The idea that had led to the circumstances you now find yourselves in...the circumstances you never want to end.