Mainly used to yell at people from when inside cars to call them fags quickly, and sometimes, confuse them.
As you pass by with a group of hooligans in your car going 70 in a school zone, you roll down your windows and yell "foig".
*a bitch-made looking group of guys pass you*
"1, 2, 3 TRIPLE FOIIIIG"
Tom: No man, it's a foig.
It came about in a text-message because "oi" together kind of look like an "a."
Preteen Asian kid #2: I can't, my mom says I have to go skating with my sister.
Preteen Asian kid #1: just ditch her, foig!