The author has repeatedly observed eight to ten-month-old infants of both sexes clasping the mother, during periods of complete security, in the form of throwing their arms about her neck, nuzzling her chin, and making rapid rotary pelvic movements for about ten to fifteen seconds. Informal inquiry reveals widespread knowledge of this behavior among mothers, but there is much resistance to systematic investigation of it. Except for mention by Brody, Escalona, and Kinsey as to related but not identical types of behavior, there is no literature on the subject. Even Freud, Anna Freud and her co-workers do not mention observing it, an indication of the extent to which infantile sexuality still remains subject to omnipresent repression. The behavior appears to be an instinctual precursor to adult coitus.