I am so thankful my kids have not yet learned an important lesson that I learned as a kid:
If you start crying, Dad will stop tickling.
I remember that when I was being tickled, I would be laughing so hard that I couldn't breathe. I loved being tickled, but I would laugh so hard that my stomach hurt. Then I found the off-switch if the tickling carried on too long - start crying. Worked like a charm.
Luckily my kids haven't found that off-switch yet. Therefore, I get in a pretty good amount of tickling each day. That's one of the simple pleasures in my life to hear my kids howling with laughter.
Mel has a different off-switch when I start to tease her. She just kicks me.