"Milk fetishism" and "lactophilia" are medical, diagnostic terms for paraphilias and are used for disorders according to the precise criteria of ICD-10 and DSM-IV.
Breasts, and especially nipples, are highly erogenous zones, for both men and women.
In addition to the sensual pleasure, women have reported feeling more feminine while producing milk and continue with lactation for emotional or sensual reasons after weaning a baby.
Or there are cases where breastfeeding was interrupted for an extended period of time as a result of infant prematurity, infant absence, or mother's illness (taking prescription medication).
Unintended milk flow (galactorrhea) is often caused by nipple stimulation and it is possible to reach normal milk production exclusively by suckling on the breast.
Nipple stimulation of any sort is noted in reducing the incidence of breast cancer.
Though such scenarios do not have erotic motivations, erotic expression may be an additional aspect of the relationship.
Some women experience sensual pleasure from pumping milk from their breasts or expressing milk manually—with or without a partner.
One hypothesis postulates that the breasts grew as a frontal counterpart to the buttocks as primates became upright to attracting mates, a model first developed in 1967.