For Freud, the oral stage marks the ages of 0-2 of a child's life, where pleasure comes from sucking, biting and swallowing (the mother's breast/milk). In 'normal' development, the child progresses from the oral stage to the anal stage upon weaning.
Yet, as Shakira has noted, a child who is not fed enough (or too much) may develop a Fijación Oral. The orally-fixated person reduces tension with activities like eating, drinking, smoking, nail-biting, and giving oral sex. They will easily 'swallow' other people's ideas.
Stills of Helen Mirren in Peter Greenaway's The Cook, the Thief, His Wife & Her Lover (1989).