I think the girls are enjoying it as well. I've noticed that even girls who aren't into tickling, so to speak, enjoy tickling guys if given the chance like this. I think most girls are somewhat ticklish, and most grow up being tickled here and there by siblings, friends, boyfriends, etc, but it's very rare for them to get the chance to get a guy in that same position, and they sort of enjoy it when they do.