I very much enjoyed reading your tale.
When you got to the point where your wife was "riding the rail" as I call it, and you note that his erection was standing straight up, I said to my self, I know exactly where this is going.
I have a couple questions for you.
When you and your wife were having sex, prior to this encounter, did you ever notice that there is a point of no return where you will keep driving and nothing will stop you. (here comes that funny feeling again
).
I have even noticed it with my wife. She may be slow to give me head, but once she reaches a certain point she will not let me get away. Holds right on and tries to get that hitch ball thru the garden hose.
As my wife used to say to the kids when they screwed up. What did you think would happen??
Did you not expect that with her rubbing her slit on his pole with your urging that at some point she would lose track of exactly where she was in the sliding cycle??
With his pole standing straight up, did you not expect that some point she would slide a little to far forward and in it would go??
It sounds like you had a great time and got good results, but my guess is that if you truly examine your intentions, then you got exactly what you wanted in the fact that your wife had sex with another man and you got to watch.
I'm not here to pass judgment on anyone, but just to ask, what was your real intention and did you really want to happen??