I think the problem is most people not into the fetish of tickling associate it with something done by their parents, older relatives. something she doesnt want in her mind when shes having sex. what you can do, and i hope this works since i havent tried it myself, but its worth giving a go, is to talk to her nonchalantly about experiences shes had being tickled by friends, ex boyfriends even. people who are outside of her, "ew thats gross" zone(sorry im tired, ill try to think of a better name). then start using it as foreplay. you need to gently ease her into this, remember. i hate saying it like this, but on some level its the same thing as trying to get her to enjoy being peed on, except tickling isnt reprehensible to most people(unless shes the most ticklish girl on the planet, in which case DO WHAT YOU MUST) lol. and you cant get your finished product in one day, you gonna have to start with something like light tickles only giving her the chills down up and down her body with your fingers, dont start digging into her ribs and pits, thats not sensual. and sensual is key. just take it gradually and im sure you'll turn her into one of us by the end of the year. 🙂