Sort your neck out

As in, get your shit together/sort your life out or perhaps, be mindful of your present surroundings..

Tommy-boy: Can't believe I've spent the gaffers wages.....again!

Benny: Tut tut tut.. You mustn't value your fingers much! You'd better sort your neck out boy or else

(Gaffer enters)

Tommy-boy: Uh-Oh

!!!!!!!SNAP!!!!!!!!