Co-worker, need some assistance

So I work with this HB8, and this girl is just cute as hell and way too chill. I met her a few years back but I just moved back into town a few months ago and just recently I find that I'm building some more rapport with her.. and i've even started Escalating kino with her slightly. We joke around a lot, I'll tell her things like I did tonight before we left like "well.. im pretty beat.. looks like the sex is gunna have to wait till tomorrow cupcake. just gunna have to settle for watchin a movie and chillin on the couch." she laughs and its a good build i think we have happening, I just think I need to get her outside of the workplace and I feel like that's my sticking point. Everytime I try and hint at .. hey lets hang, it always comes out as sexual innuendo and I think maybe that might be my own wrong doing. She doesn't get offended.. I grabbed her bum earlier and told her she should start doin pilates jokingly. I just think I might need to start sendin a different vibe so she doesn't see me as some douche and can lower the Bitch Shield. Any advice on this situation would be much helpful.