Well my girlfriend who I dated since we were both 16 and is now my wife isn't ticklish at all. Once in a blue moon I'll hit a sensative nerve but 90% of the time, NO SHE ISN'T!
My wife can keep it bottled from anyone normally except after I bring her to a huge climax, then the circuits blow and for a little while I get a super ticklish playtoy. It does not last too long but it is great fun while it lasts.