Wiktionary
flehmen
n. (lb en especially in the compound "flehmen response") Flaring of the lip in mammals, associated with intensive smelling; flehming. vb. (alternative form of flehm English)
Usage examples of "flehmen".
Her upper lip curled in what biologists call the Flehmen Response, instinctively directing the current of air into her nostrils, and then she sniffed again.
Maggie recognized the classic Flehmen response of the male to a female.