A couple I knew went for a long romantic walk on a summer evening in the fields....
... and as you do, when they'd crossed several fields and felt they were truly in the middle of nowhere, got a bit frisky and settled down for some lovin' in the grass.

He lay down, she disrobed and started bouncing up down on him - she was a big lass - and great fun was had until she sat up for a breather and noticed something moving in front of her...

Yes, it was a packed evening commuter train, rolling cautiously along at walking pace on the subsiding embankment barely thirty feet away, many interested faces plastered to the windows.

Back then there were no digital cameras or mobile phones so their secret's safe.

Edit: having noticed that Crewe trains often crop up here in rolling stock sex-related anecdotes, I'm pleased to disclose that this took place the late 70s next to the Manchester line between Sandbach and Crewe. Near the sinking tree.
(Juan Quar is clinging to her front teeth on, Thu 23 Apr 2009, 21:13, Reply)