The best thing about tickling, as opposed to say, sexual stimulation, is that you can do it on practically any part of the body. It turns your partner's entire body into a canvas of erotic touch. When you're about to get tickled you get goosebumps when they hold their fingers over your body without even touching and your lips start involuntarily twitching into a smile and you instinctively wanna wave their hands away. You just start to feel vulnerable all over - you feel naked even if you have clothes on, like any part of your physical form can be exploited and turned against you. And when he finally digs in you shriek and you squirm and you love it and you hate it and you want it to stop and you never want it to end. With tickling you can make a cute boy giggle and beg for mercy. Even a tough guy can't disguise how sensitive they are when being tickled.