Adult lactation means breastfeeding of an adult partner or re-lactation for primarily erotic reasons. Depending on the context, other terms are used such as adult suckling, adult nursing, adult breastfeeding, Adult Nursing Relationship (ANR), or nursing couple(s). The scientific-sounding terms Milk fetishism or Lactophilia as well as paraphilia (in this context) are incorrect according to the definitions of ICD-10 and DSM-IV. In scientific terminology, these would be disorders – the diagnoses of which should be based on precise criteria. One non-exclusive element of said criteria is that an individual is suffering from such a disorder. Therefore Milk fetishism or Lactophilia should also be avoided in colloquial speech.
Breasts, and especially nipples, are highly erogenous zones (both for men and women). One hypothesis assumes that during evolution, those women prevailed who were motivated by physical pleasure to nurse their babies in the best possible way. The same holds true for the lips, also erogenous zones where pleasure may have lead to "kiss feeding", in which mothers chew food before passing it on to the child.
Because female breasts and nipples are normally an important part of sexual activities and perception, it is not surprising that couples may proceed from intensive kissing of the nipples to actual breastfeeding. In lesbian partnerships, mutual breastfeeding has been regarded as a familiar expression of affection and tenderness.
In its Sunday issue of March 13, 2005, the London daily The Times gave a report of a scientific survey (comprised of 1690 British men) revealing that in 25 to 33% of all couples, the male partner had suckled his wife's breasts. Regularly the men gave a genuine emotional need as their motive.
Beyond these, there exist hardly any reports or investigations. Nevertheless, from European Middle Ages a multitude of subliminally erotic visionary experiences of saints have been passed on in which breastfeeding plays a major role. One prominent example is the Lactatio of Saint Bernard of Clairvaux. Generally speaking this was a rather strong taboo, and it can be concluded that an adult man suckling for milk is in contradiction to well established images of masculinity.
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.