Shake hands with me: Slip me five so I know you're alive(1926+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with slippery-slope
A dangerous course, one that leads easily to catastrophe, as in He's on a slippery slope, compromising his values to please both the bosses and the union. This metaphoric expression alludes to traversing a slick hillside, in constant danger of falling.