Imagine some shipwrecked men drifting aimlessly on the ocean in a lifeboat. As the days pass under the scorching sun, their rations of food and fresh water give out. The men grow deliriously thirsty. One man ignores all previous warnings and gulps down some salt water. He quickly dies.
Ocean water contains seven times more salt than the human body can safely metabolize.
A person dehydrates because the kidneys need extra water to flush the overload of salt. The more salt water someone drinks, the thirstier he gets. He actually dies of thirst. Lust is like Salt water. We thirst desperately for something that is forbidden.