We quickly called in at my brother-in-law's on our way up North last Wednesday. We timed it perfectly to surprise my 6 year-old nephew by picking him up from school. It was worth the detour just to see the look on his face.
Once home we had the following conversation:
Nephew: I'm very ticklish, I'm the Emperor of Tickledom
I instantly turn into the Tickle Monster and administer a vast amount of tickling amidst flailing limbs...
Nephew: Heeee, heee heee, squirm, squeal!
Me: I see - you really are very ticklish aren't you?
Nephew: Yes, my sister tickles me a lot - for as much as half an hour at a time!
The Tickle Monster appears again!
Nephew: Heeee, heee, heee. Let's see if you're ticklish now Auntie
Me: No reaction
Nephew (admiringly): You're not ticklish at all - that's because you're very tough
These are moments to treasure...