basically it's fine and she wants it if she is already ok with you being that physical. All you have to do is to follow the right steps and escalate comfortably. I would go for hand holding kino and if she complies, go for a arm around shoulder or arm in arm as you walk. If she complies again, go in for a kiss. Do all of this of course outside of the work area and bounce her from location to location. Just ask her to come help you shop or make up some excuse for her to hang out with you so you can do all these kinds of things. Try and keep it flirty but not too jokey and make it seem like you actually are trying to get with her instead of just kidding around. Ease back a little and pretend to be distracted if she doesn't comply.

When she says not to threaten her with a good time, just reply with: what are you gonna do about it?
Say this in a sassy kind of manner with a smirk on your face that matches her energy level.