screw around

Fool around aimlessly, accomplishing nothing, as in If you boys would stop screwing around we'd have the fence painted in an hour. It is also put as screw around with, as in Stop screwing around with the new camera. The idiom probably derives from screw in the sense of “turn” or “twist.” [Slang; second half of 1900s]

Be sexually promiscuous, as in He's been screwing around behind her back for years. [Vulgar slang; first half of 1900s]