 The association of pleasure and nutrition holds true as well for the lips, also erogenous zones, where pleasure may have led to "kiss feeding", in which mothers chew food before passing it on to the child.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.