"Blowing It" at the last minute or "Sucking" when it counts the most.
Derived from the 2013 Super Bowl where the San
Francisco 49ers had three opportunities to score the winning touchdown at the five yard line at the end of the game and decided to pass, ruining their one sure shot at the title.
The
definition also suggests it can be a term for last minute
oral sex.
Person 1: "How did the game
go?"
Person 2: "We would have won but the qb decided to 49 it!"
Alternate
definitionPerson 1: "Where is Jim?"
Person 2: "He is probably 49ing before
work."