MRS. REAGAN was starting up the steps to a helicopter on the White House lawn recently when the Reagans' dog, straining at the leash she was holding, lunged ahead of her and nearly knocked her over. The dog, Lucky, was acquired by the Reagans last year and has since been the impetus for several brief news stories containing phrases along the lines of "stumbled but recovered her footing" and "the president was able to untangle himself, however." It has also provided TV footage suitable for closing the evening newscasts on a light note.

This sort of thing happens at the White House. Presidents must have pets, and if you have pets you have to live with them. Given these circumstances, presidents as well as the rest of us would do well to become familiar with certain standard manuvers practiced by household pets. The following list is based on observation and experience over some years. It is worth memorizing to avoid embarrassment even if you are not subject to heavy media coverage when you board your helicopter:

Dog acting alone: 1)Dog being walked wraps leash around parking-meter post or man's legs. Man releases leash preparatory to unwinding it. Dog breaks free, attacks neighbor's German shepherd. Man pays all veterinary bills. 2)Dog begins barking furiously at 3 a.m. Man awakens, peers down staircase. Dog runs back, curls up on man's pillow. Man attempts to lift dog off. Dog yelps as if sore spot has been poked. Family wakes. Man gives up and sleeps without pillow, gets crick in neck.

Cat acting alone: 1)Cat conceals self in closet as dinner is being prepared. Family fears cat is trapped in a wall, begins frantic search of house. Search moves upstairs. Cat emerges from closet, eats whole salmon in kitchen. Bell rings. Dinner guests arive.

Dogs and cats in combined maneuvers: 1)Dog pushes water bowl to center of kitchen floor. Man enters with two bags of groceries. Cat crosses man's path. Man stumbles over cat, steps in water bowl, spills groceries. Man goes to change milk-soaked pants. Dog eats chuck roast on floor. 2)Dog barks at front door at night. Man opens door. Man is distracted by sound of retching from cat on couch. Dog bolts for freedom to seek female dog in neighboring state. Cat eats dog's food.