I have the Sun in Leo. Leos like to be playful and let off steam, but they also like to have centre-stage and be dramatic and dignified.. If Leo was the only part of my nature, I am not sure I would be that interested in tickling - too undignified, and too much about the Lee rather than the Ler. (I'm a Ler.)
BUT, I also have Moon and Ascendant (Rising Sign) in Scorpio. AND I have Mars in Gemini in the 8th House.
Scorpio is fascinated with subtle power and delving into the depths, and seeing what makes people tick and working out how to manipulate and control, partly as a defence mechanism. It is interested in sex and meaningful intimacy as a death and rebirth experience. The 8th House is related to Scorpio and has to do with the same areas of life.
Gemini is highly-strung and lives on nerves and is skittish and playful.
Mars shows the kind of energy you use to assert yourself and get what you want and need.
Put all those together and I can see why I am drawn to tickling, since it is an activity that is superficially playful yet at the same time can be a powerful expression of intimacy and power.