There's something so very predictable about taking a chick back and sleeping at your place, and what it could mean for the future is even more predictable. Hence, it's best if you shake things up from the start; keep her on her toes and don't play into the expected or the obvious. Maybe the night should include a card game, a funny movie or an impromptu dessert-making session. Use both your immediate and general environment -- if it starts snowing at 2 a.m., get her outside to build a snowman, or if the power goes out in your place, have some fun with flashlights and scary stories. All of this may sound somewhat juvenile, but not only do most women respond very well to this kind of erratic, "big kid" personality, it also never shifts to full-on romance. The evening can be all about fun and passion, and all you have to do is remain completely unpredictable from the moment you return. She won't know what to expect, which means she won't make the snap assumption that you're looking for anything long-term.
If you just sit back and let the evening play out on its own, you may fall into the standard scenario, and the passionate "oops, I let an 'I love you' slip" moment is lurking in the shadows. Once that happens, nothing can save you.
When sleeping at her place, I suggested you come fully prepared with an "excuse rolodex" just in case one of two things happened: the night wasn't quite so great and you had to hit the ejector seat early, or things went a little a too well and the situation was spiraling out of control with hints of commitment everywhere. Well, when you're sleeping at your place, you can really enhance any excuse you might have to use.
When hitting up girls in the clubs and bars, it's often advisable to have a wingman, correct? Given this fact, if the night isn't progressing quite as planned and you find yourself getting painted into a corner, keep a remote wingman within striking distance. For example, if you're looking for a way out in the morning, text him a quick message to call you early with a feigned need. The options are limitless, and provided your pals are reliable, you won't have to go it alone when spending the night at your place. This doesn't necessarily mean you're trying to get away from her, either; it simply means you want to keep things casual, which isn't inherently insulting.