I've occasionally been in circumstances where I was inclined for other reasons to remain motionless, and for that reason someone decided it would be a good time to tickle me. I've never lasted for very long.
In one instance I was lying on my back on the floor, shirtless, with a bunch of stuff stacked on my chest, which sounds weird until you consider that I was in college at the time, college is the time for doing idiotic and pointless things.
I was in my girlfriend-at-the-time's dorm room, for whatever reason, with my shirt off, for whatever reason, and lying on my back I’d found myself with three hardback textbooks stacked on my chest. This led Rachel into a delighted game whereby she stacked book after book, hardbacks and paperbacks, and thena couple of notebooks, and then other random items like a stapler and whatever empty aluminum cans she could find in her room (all Mountain Dew; Rachel really knew how to live it up).
By the time she was finished, the stack reached several feet into the air. By the time we’d finished with the cans she was kneeling on the floor and giggling uncontrollably; I was fighting the urge to laugh because any undue motion of my chest or torso could bring the pile crashing down.
So finally I said, “Okay, enough, take it down.”
And Rachel, through a punchy smile, said, “No.”
“What do you mean, ‘no?’”
She said, “First I’m gonna play with your tickly places.”
She knew where all those places were, of course, and like I said, I didn't last very long; motivated by self-preservation, I struggled mightily to stay still as her fingertips scampered wickedly along my skittish stomach and sides but before long the tower of stuff was swaying and trembling, and not long after that soda cans and staplers were plummeting perilously close to my head.