Wiktionary
four f's
n. (context chiefly jocular and euphemistic English) A set of four basic biological instincts, commonly listed as "Feeding, Fighting, Fleeing and Fucking."
Usage examples of "four f's".
He once again reminds Lindstrom of a puppy, which -- he realizes-- is a bit true of most young men when they are not preoccupied with one of what stress psychologists refer to as the four F's -- fight, flight, food, and eroticism.