When two people simultaneously give the Nazi salute to each other and their hands meet in a high five, thus the name Heil Five.
Nazi Shithead #1: hello fellow facist wow that is a nice swastika
Nazi Shithead #2: why thank you
Nazi Shithead #1: yes that deserves a Heil Five
(they proceed to heil five)
when two people attempt to give each other a high five, but miss, resulting in two unintentional Nazi salutes
Hey man, Archibald and Chester of the checkers team must have poor eye-hand coordination because they just heil fived each other.