Final answer:
During the phallic stage of psychosexual development, the primary source of pleasure for a child is genital stimulation.
Step-by-step explanation:
The child's primary source of pleasure during the phallic stage of psychosexual development is genital stimulation. Freud's theory suggests that during this stage, which occurs roughly between the ages of 3 and 6, the child becomes aware of their own body, focusing on the genitals. The phallic stage is marked by the development of the Oedipus complex in boys, where conflict arises due to the child's desire for the opposite-sex parent and the subsequent rivalry felt towards the same-sex parent.