Psychosexual stages of development:
-Oral stage (0-18 months) mouth, lips and tounge become in the erogenous zone. Infants gain pleasure from things like sucking thumbs.
-Anal stage (1.5-3 years) gains pleasure from expelling faeces and urine. Conflict during potty training. Anal fixation is too harsh/lenient.
-Phallic stage (3-6 years) genitals become part of erogenous stage, become aware of sex differences. Boys/girls gain pleasure from genital stimulation.