Another vote for wedding night sex between two virgins. Perhaps some of the lousiest sex we ever had - but at the same time, the most intense, most significant, and most meaningful. (And for us, Igor, it was 5 sessions in the first day - I recall that at least one of those involved two instances of intercourse.)
Other "best sex" would have to be some of our outdoor experiences. We've done it in both daylight and darkness, in secure locations as well as where there was risk of being seen. (A few times, I know we were seen.) There's something very sensual about being naked together outdoors. Too many cases to pick just one, but if I had to it would be the time we were in the water, after dark, about 20 or 30 yards off a public beach in Florida.
And there's the first time she had "sequential orgasm", and passed out on me. Obviously ultra intense for her - but perhaps the most frightening thing I've ever experienced, thinking my wife had died of a heart attack or seizure while we made love. Fortunately she was out for only about 5 seconds.
And there was the overnight train, Chicago to New York, when we had a roomette to ourselves. Somewhere east of Cleveland we dimmed the lights, opened the drapes and made love in the gently rocking railcar while the world rushed by outside the window.
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