What is 1-26?

The day Australia Day was cancelled in Western Australia after a plane stalled and crashed into the Swan River killing two people.

"1/26?"
"Yeah dude, not as impressive as 9/11"

1-26 - meme gif

1-26 means when someone does something very stupid and now regrets what they've done, usually this involves any form of sex( oral, anal, group ect.)

are you going out with him?
no we just 1-26ed it, ugh i wish i didnt!