I get what she's saying. Part of the turn-on, for the girl, is having the guy completely take control...and in turn, she loses complete control. Part of the turn-on is being 'forced' to stand something she wouldn't outright ASK for. (I don't say 'forced' in a scary disrespectful way, but you know what I mean, ..in a playful trusting way but nonetheless not something you would ask to have happen). It's hard to explain I guess, but I get where she's coming from. If she asks for it straight out, it takes away a little bit of that power play that is one of the biggest parts of the turn-on. ....It's almost like,..GIVING someone the one-liner to 'get you back' for being a smart-ass to them. It's an attractive quality when you can go back and forth w/someone naturally, and provide that natural competitiveness for eachother, feed off eachother, one-up eachother, outwit one another. It's flirting. If you have to GIVE the other person the responses, it's almost like playing with yourself. You're not being stimulated in the same way. It doesn't feel completely genuine and natural. You always wonder...are they just doing this to push my 'turn on' buttons b/c i said i liked it, or do THEY get turned on by it? ...All valid points that guys will do pretty much whatever you want happily if you say it turns you on (and they will), and that as your bf, he should WANT to do those things which turn you on(and he should)....but what she is saying is a BIG part of the turn-on for her is him doing it b/c HE likes it, b/c HE likes playfully getting the best of her, etc etc....so really, to give that up by just telling him would take away the game for her (and it is a game) and take away a part of why it's a turn-on in the first place. Am I making any sense?
That all being said,...my advice is,...be super playful with him. Let him know you don't take playing around too seriously and that he can joke w/you and poke fun at you and wrestle with you, and (tickle) you without you getting (actually for real) mad or reacting badly to it. Alot of girls get weirded out by too much tickling or rough-housing, so he may be playing it safe till he feels you out. If you start with him consistently, and then react favorably when he gives it back to you, he'll have fun too and want to keep pushing it with you. If you get into a situation where he (or someone else) DOES tickle you...just play it up, so it intrigues him and knows it's fair game. There's always ways to hint, steer conversations, react...to give people signals to what turns you on without telling them and taking away that aspect of it for you. Positive Reinforcement goes a long way!!
And P.S.: ...in MY experience, ...MOST guys, (even the ones who don't belong to this website), find tickling a girl to be a turn-on. I always thought it was just a guy thing. And at the very least, they usually find it sexy, playful, funny, cute, fun, amusing..... so i think you're safe. THEY are the ones that have to worry, b/c alot of girls don't like it, or too much of it.. so you're safe there too!