"Summer Rain" by Sven the Elder (sven@brass-neck.demon.co.uk).

A man is out in a boat fishing, while the woman who is with him reads a book. It starts raining, and so they stop fishing and reading and fuck.

That's about it, except that the author adds some supplementary words, phrases, and ideas. Suddenly pendulous, pirouettes, bobbing breasts, shivering, confluences, sweet roundness, rain-diluted juices, straddling, gasping, savage proportions, and more bobbing and shivering and rain-slicked foreheads. And the idea that these two people have had a long history together.

I guess if you add those words and ideas, this becomes a most interesting little story.