As I said earlier, for Freud, the sex drive is the most important motivating force. In fact, Freud felt it was the primary motivating force not only for adults but for children and even infants. When he introduced his ideas about infantile sexuality to the Viennese public of his day, they were hardly prepared to talk about sexuality in adults, much less in infants!
It is true that the capacity for orgasm is there neurologically from birth. But Freud was not just talking about orgasm. Sexuality meant not only intercourse, but all pleasurable sensation from the skin. It is clear even to the most prudish among us that babies, children, and, of course, adults, enjoy tactile experiences such as caresses, kisses, and so on.
Freud noted that, at different times in our lives, different parts of our skin give us greatest pleasure. Later theorists would call these areas erogenous zones. It appeared to Freud that the infant found its greatest pleasure in sucking, especially at the breast. In fact, babies have a penchant for bringing nearly everything in their environment into contact with their mouths. A bit later in life, the child focuses on the anal pleasures of holding it in and letting go. By three or four, the child may have discovered the pleasure of touching or rubbing against his or her genitalia. Only later, in our sexual maturity, do we find our greatest pleasure in sexual intercourse. In these observations, Freud had the makings of a psychosexual stage theory.
The oral stage lasts from birth to about 18 months. The focus of pleasure is, of course, the mouth. Sucking and biting are favorite activities.
The anal stage lasts from about 18 months to three or four years old. The focus of pleasure is the anus. Holding it in and letting it go are greatly enjoyed.
The phallic stage lasts from three or four to five, six, or seven years old. The focus of pleasure is the genitalia. Masturbation is common.
The latent stage lasts from five, six, or seven to puberty, that is, somewhere around 12 years old. During this stage, Freud believed that the sexual impulse was suppressed in the service of learning. I must note that, while most children seem to be fairly calm, sexually, during their grammar school years, perhaps up to a quarter of them are quite busy masturbating and playing "doctor."
In Freud's repressive era, these children were, at least, quieter than their modern counterparts.
The genital stage begins at puberty, and represents the resurgence of the sex drive in adolescence, and the more specific focusing of pleasure in sexual intercourse. Freud felt that masturbation, oral sex, homosexuality, and many other things we find acceptable in adulthood today, were immature.
This is a true stage theory, meaning that Freudians believe that we all go through these stages, in this order, and pretty close to these ages.
The Oedipal crisis
here he is
go here also