screw around

1. 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]

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