You would use the term when you think it would be in the be in the best interest of the party/s or person/s confronting you to leave and/or leave you alone. It should be stated with feeling.
You best step-off, mother fucker!
by W. Steward April 20, 2004
Church for gangsters.
"You better go to Step Off and pray"
by asian_gangsters November 03, 2008