Smack On means to propose a fight with someone. Generally in a joking manner but can definitely can be used very effectively in a real situation. Smack On is closely associated with the term "punch on".
Joking:
Luke: "You suck apples"
Brad: "Smack on cunt"

Serious:
Josh: "I fucked your ex on a trampoline!"
Ryan: "Smack on cunt!"
by KinnyMcbinspin February 4, 2014
Get the Smack On mug.
1) The sound a thumper makes when it busts off

2) A common adlib used by certain rappers from North Oakland (Lil Rue, HD, etc..)
"Every day it's like I got some new niggas to kill (SMACK SMACK)" - HD on Minister Of Defense / Extortion Muzik 2
by yay area representative March 31, 2011
Get the Smack Smack mug.
The more updates name for "sandles" or " flip-flop".
Derrived from the sound the "shoe" makes when hitting your foot.
by Cher-in-Surrey November 2, 2010
Get the Smack Smacks mug.
Appear to have a quality of something positive or negative
The new iPad smacks of inconvenience.

This party totally smacks of awesomeness!
by Bigg Phill January 27, 2010
Get the smacks of mug.
Heroin. Most frequently used in the 60s.
When the smack begins to flow, I really don't care anymore...
by Lurhstaap December 29, 2004
Get the smack mug.
To have sex from the back, hit it from behind, doggystyle. Doing this hard and fast so that it makes a smacking noise.
That girls hot, I want to smack that.
by jennw January 13, 2007
Get the smack that mug.
usually used while eating some good ass food
by k money bitch June 13, 2017
Get the smack mug.