1) Be evasive. Never commit to plans in advance; it will be your death knell. Employ the phrase "let's play it by ear" judiciously. Additionally, if your boys find out you're ditching them on a weekend night for the ugly girl you bang, you will never hear the end of it.
2) Act completely uninterested 99% of the time the two of you spend together. Everyone knows that the worse you treat someone, the more they want you. Start out by ignoring her calls and you'll get a handjob; piss on her mom's grave and you'll be knee deep in ass plunderage.
3) If she asks why the two of you can't date, write an incredibly detailed list of all the attributes you most desire in a member of the opposite sex and ask her how many of those qualities she possesses. Zero can be a harsh reality.
4) If you're feeling smothered, get absolutely plastered Friday night to the point of being bed-ridden all of Saturday, enabling you to guiltlessly avoid hanging out with her for the remainder of the weekend. "That's sweet that you want to take care of me, but I'd really rather you didn't see me in such horrible shape."
5) Remember, there's a reason you're stringing her along: you don't see a serious relationship forming. However, to continue unemotionally fucking, you'll have to occasionally suffer a weeknight sleepover. For those not dating anyone they actually care about this can be incredibly painful, but if you want to continue having drunken sex at 3 a.m. Saturday night it's a necessary evil.
6) In conjunction with #5, don't let her continue to sleep in the morning if you have to leave for work unless you know you'll come home to find your bed made and the shorts you gave her folded and not tossed on the floor.
7) Completely lose interest in her the moment you come. Go IM people, toss on the TV, bake cookies - she's your fuck buddy, and even if she doesn't see things the same way, you've got shit to do.
8) Don't tell her you love her. This is just sheer lunacy, and may get you one or two more rolls in the hay, but is 100% not worth it.
9) If she starts losing interest, hem and haw your way into convincing her the two of you might actually have a future.
10) Enjoy it for as long as you can. She'll figure you out eventually; they always do.
