OK, I would not suggest introducing it as some new wave health benefit.
There is no guarantee that the woman (I hope you ain't playing with girls) you want to tickle will be OK with it. That said, if you're both interested in each other, bringing it up in a nonchalant way, feigning confidence if you have to, avoid the word "fetish," and just express that it's something fun and sexy and she should try it sometime, you might get a positive reaction. At worst, the lady might express not being into it and that's understandable, gotta respect that, but if they're mean or cruel about it, that's probably a red flag of someone judgmental and inconsiderate anyway.
The worst thing to do is bring it up in an ashamed embarrassed way. I think it makes things a bit too serious and the conversation to follow tends to be colored by that negativity.