The old pros cavort grandly. Moore even strips down to a black bra and panties, and rolls in bed with her husband (George Se-gal). Still, Russell, who directed the wonderfully weirdo incest comedy “Spanking the Monkey,” has more balls in the air than he can juggle. His point is well taken: your parents will make you nuts, no matter who they are. But “Flirting” strains too hard for laughs. By the end, it’s revving crazily, like a car in the wrong gear. Mel learns to relax. The movie never does.
