First rule of asking for OTC: Depending on area and club, you'll likely get a lot more "no" responses than "yes" ones. Even after decades, I still get lots more declines than acceptances.
Second rule: Even a "yes" or "maybe" has a good chance of being just a way to get you to come back to the club and spend money, and not a real agreement.
If you really want to meet her OTC, spend a fair bit of time in the club with her, even before asking her about it, Sitting, talking, drinking, eating, whatever. Don't be stingy. Tip her on stage. If you're in a club, like many of those in Louisville, with "dancer drinks", buy her a couple. If not, slip her 10 or 20 every so often while she's sitting with you. Buy food. If she's been sitting with you for a while, "I'm gonna get some food. Do you want anything?" has been a good way to get her to sit with me for extended periods of time. Don't over do it, but don't be a cheapskate.
And if she says no, do NOT get belligerent or ignore her in the club. Remember, they get asked all the time, so even if she seems upset, be polite, and say something like "OK, if you change your mind, let me know. How about we go get a dance or two then?" If she says no, say nothing about money, even if she asks. "We can talk about that if you ever change your mind."
If she says yes, or questions what you're gonna want to do, I still don't suggest talking about money. Just be upfront and clear, "I'd like to have sex. More privately."
Some girls won't want to continue the discussion unless you do talk about money. Those are likely to be girls who do OTC regularly. If you're fine with that, go for it. I personally only do that once in a while, when I'm between regulars; I prefer girls who don't do it often if I can find them, and believe they don't. If you just want to get your nut in a place that's more private than a club, it's not a horrible place to start while you learn the ropes. Girls who do it regularly will be much more transactional than what I generally go for, e.g. if they start talking about "per hour", or "per session", or similar.
Again though, it's a place to start, just be aware that's what you're getting. One of the absolute best cocksuckers I've ever met was high as fuck volume, but she was so very worth it. She'd get me off in five or so minutes and keep going for the next 20 to 30 minutes to get me off again. Then she'd just lay there and play with me for a few minutes and do it again. Only person I've met who could routinely get me off more than once in less than about an hour.
ITC extras do not automatically imply a willingness to go outside. In fact, it can mean OTC is even less likely, unless she's really low volume. If she figures she's safe doing it in the club, she might not want to risk meeting someone she doesn't know outside. See all that stuff above about cultivating a "relationship". Hell, even if she's a firm no, circumstances can change, and she'll remember who's been nice and who's been an asshole.
Polite persistence, not pestering, spending money, and being a regular can open doors, and legs. So don't give up yet.