Ferry fun
 

Many years ago, I was taking a late-night ferry trip, last sailing of the night, half empty. Went to sit on the top deck, rows and rows of seats, and the only other people up there were a couple seated 4 or five rows in front of me and to the left.

Nothing unusual, but after a while I noticed the woman, apretty 20-something brunette with long hair, kept looking furtively around. This raised my suspicions and I paid attention and soon noticed her right arm was moving up and down in a steady motion and her hand, which I couldn't see, would have been in her man's lap.She kept looking carefully around, though no one showed up, and didn't bother looking back where I was since I wouldn't be able to see anything, and no doubt figured I wouldn't figure out what was going on anyway.

This went on for a few minutes and then the woman looked around really intensely and then, presto, I saw her head dive down into her guy's lap, where it remained for about 30 or 40 seconds, subtly moving up and down, and finishing the job.