DISCLAIMER: I DO NOT PARTAKE IN ONE-NIGHT STANDS!!!!!
The Plan: Go in hard and heavy. Be blunt and tell her you are not looking for a relationship. Oh yeah and keep a picture of some woman(Ex, sister, Cousin, friend) in your wallet. Wave it in her face if things get ugly, and pretend that’s it your current girlfriend.
The Reason: Hook-ups are about sex, not feelings and emotions. It should be ok to make a clean break with minimal fuss. Tell her how hot it was, but that you just acted out.
The Catch: If the one-nighter happens at your place, then it might be a littke tricky getting her to leave. I always suggest, saying these things, when she’s near the door. If the one-nighter was at her place, you might have things thrown at you.