When he didn't get the pay raise he was expecting, he had to take another job to 'pick up the slack'. [=to make up for the money he was not making]
The manager has to 'take up the slack' when employees don't do their jobs correctly.
We left some 'slack' in the budget so that we can hire more people if we have to.
(..) Aah! Ah! Hey, foom foom... I hate to do this to you, but you Think you could Help me pick up the slack on those etch-a-sketches? No problem. I appreciate it. Buddy is killing me. I already got lum lum and choochoo pulling' doubles. That was quick thinking yesterday (..)2003 Elf