To put your a** in a sling

Posted by S. Ryan March 11, 2003In reply to to put your a** in a sling posted by Bruce Kahl on March 11, 2003

If you know, please tell me what does it mean? thank you in advance.

Here in the NE part of the US of A the phrase means to stay out of trouble as in:
"I just started this job and I will show up on time so I don't get my a** in a sling."

This actually means to be "in" trouble, as in having your broken arm in a sling. "I did not do what I was supposed to do, and now I got my a** in a sling."