Hey there!
According to Freud, there are five stages of psychosexual development. In order, these are oral, a.nal, ph.allic, latent, and g.enital. The first stage is the stage that babies goes through from birth to about one year old, and they derive pleasure and sense from putting things in their mouths. This is why pacifiers and such are very popular, but can become a problem if they have it for too long.
Because Clarissa feels the need to keep things in her mouth, she's likely fixated on the oral stage of development.
Hope this helped you out! :-)
