I'll have to agree with all the 'lers who said that cursing was a good sign that they were doing something right.
I'd classify myself as somewhat antagonistic as a 'lee - I'll make wiseass comments, spout ego-deflating remarks, or pretend to take a nap or feign boredom while you're trying to get a ticklish reaction out of me. But if you're a good 'ler (or a lucky one 😉) and get me laughing (not just giggling, but REAL laughter), then all my defenses usually go out the window and the cursing ensues. It's not a conscious decision, it's something that happens when the tickling has become really intense.
Believe me, if I could control that reaction I would because (in poker terms) it's too much of a 'tell'. It gives the 'ler a clear sign that the tables have turned - and that's not something a stubborn 'lee EVER likes to admit. If you've got me cursing like a sailor after his first six-pack, then you've successfully broken down all the protective walls I put in place, and you can bet that within a couple of minutes, the cursing will give way to full-blown begging. And if you can manage that, it'll be something I'll both love and hate you for 😀