I'm 75-25 on the "ler" side. It has to be a two way street. My last relationship consisted of a woman who sure loved doing it to me, but really wasn't ticklish herself. There was only one place on her that produced a positive reaction: down in her, shall we say, nether regions. And, if you have clothes on, and people are over, how the hell can you go THERE? Let's face it, tickling is a big, big part of my sex life (and it's a big part of the sex lives of most of you, from what I've read), and if it's only going one way, then it can't last. It didn't.
I've always been the "ler", I didn't find out how much fun it was being a "lee" until recently. My Number One gets a tremendous kick out of applying it, in fact, while she's doing this, she's laughing even more than I am!
I feel tremendously lucky to live this part of my life, let me tell you.