Unholy Low-Five 

The act of going in for a high five... but swinging it 180 degrees so that you effectively slap the genitals of the intended target.

Fool was trippin' on the court so I slapped him with an unholy low-five.

Unholy Low-Five by Big Jiggity November 16, 2010

uhholy low-five 

When walking in a line or near others, your arm accidentally dangles into the junk of another person.

Whoops! I didn't mean to give you the unholy low-five here in this DMV line. My bad.

uhholy low-five by Duke January 22, 2003