Everyone is born with a basic sex drive, or instinctual energy, called the LIBIDO (Latin for ‘desire’). The sex drive has both mental and physical features. These features are: 1. an internal organic source of excitation 2. a quantity or pressure of excitation 3. an aim, which is to achieve a sensation of pleasure by removing the pressure 4. an object, which is a thing or person in reality required to satisfy the aim.