Tickle my underarms & I flap like a recently decapitated chicken.
I once lay there & let the wife loose, tried to grin & bear it.
That did not go well lol
On the back of my knees.
I’d laugh and scream till my sides literally hurt lmao!!! When the sensation of being tickled gets to you, but on the inside you’re angry and you laugh anyways…UGH!!! ☺