This entertaining video explains the differences using food as props:
http://www.youtube.com/watch?v=q64hTNEj6KQ
4. Never Refuse Sex As A Punishment Or Use It As A Rewarderrrrr someone does not like my on the side business
In the bad old days, some women were led to believe that the way to get a man to toe the line is to offer sex for good behavior or withhold it when the man has displeased them. Most of us today recognize this as hateful behaviour and a recipe for disaster.
Men don't want to be controlled or punished, especially around sex. They don't want to be made to feel like little boys. When we're hurt or angry at our partner, we need to share our feelings with him in an adult way. We can even say that we're too upset for sex, right now. What we mustn't ever do is make him feel like we're deciding when he gets to have sex, based on whether he's been "good" or "bad."
On the other hand, using sex as a reward turns us into sex objects and makes sex into a commodity for our partner to "earn." It's no longer two people being intimate or enjoying each other. Commodifying sex makes it into a business transaction and our bodies then become objects for trade.