The act of which a user, in a format such as discord, posts something, then you, wanting to post something as well, do so, only for that person to post something similar (Slightly edited, or the same thing), basically throwing a fit because they're not getting attention
Jim:Ooh this drawing I spent HOURS on is done, I'm gonna post it!
KYLE:Ooh no! Someone posted after I posted MINE?! IM GONNA POST IT AGAIN
Jim:What the fuck dude, why are you sandwich posting me?
definition 1: the letter "a" is used to speak with out sounding like a caveman
definition 2: a vowl
definition 1: "HOLY CHEESE PUFFS a SPIDER MADE OUT OF KNIFES"
definition : "hA hA hA!"