The first thing I notice about a woman is her hands and her arms -- and since those are directly involved in her tickling me I guess that makes sense.
I'll also note that out in the real world, in candid and platonic situations, a ticklee doesn't necessarily always have a lot of say in who tickles him -- the tickler chooses him. I've had several experiences where a woman I wasn't at all attracted to finds out I'm ticklish and then becomes a recurring tickler over the course of our acquaintance, and it's a pleasant development -- our relationship, though still platonic, becomes warmer and more agreeable, and I do in fact become attracted to her.