In a football match when a player is pissed off, he maygo into a challenge and snap the opposition player. This is know as a lash. And so the player has just lashed out
Person 1: “No need Brendan!”
Person 2 “What did he do?
Person 3 “He just lashed out on niall”
Person 4 “Brendan chill out!”
Synonymous with:
Get pissed, get wasted, get hammered, get rat-arsed, get sloshed, get trolleyed etc
The word 'lash' orinally means to strike with a whip, and so has this extended meaning (ie. drinking makes you feel like you've been flogged).
NB. Usually used in a positive sense.
1. "Hey John, what are you up to tonight? The boys are all going out and getting lashed"
2. "The boys are all going out on the lash tonight."