Only one model I played with ever done that. Of all the years I've been the lee and all the women I've tickled, she was the only one who got to the point of saying, "Okay! Okay! I've had enough!"
A gal who loved being tied up helpless and tickled silly, she was extremely ticklish and trashed around quite a bit, yelping and laughing and punctuating with Oh boy, Oh God, and the like. She couldn't get enough of it, and sometimes when I thought I was getting overboard, I'd stop and ask how she was doing, and when she caught her breath would always say she was fine or that was fun. However, getting around the two hour mark on our first session, I started sucking on her toes, which sent her through the roof. After about ten minutes of that she finally yelled out that she had enough. Later she told me I was one of the best ticklers and came back a few months later for a second round. That gal just can't get enough and loves it all. I love women like that.