Eli Manning Flips Double Middle Fingers During Live 'MNF' Broadcast

The Manning broadcast turned PG-13 on "Monday Night Football" ... with Eli Manning giving a double middle finger salute LIVE ON AIR!!!

The hilarious moment went down on ESPN2 as the Giants legend was sharing his experiences going up against the Philadelphia Eagles ... describing their fans as absolutely ruthless.

"You go to Philly, you're getting the double bird right away from a 9-year-old kid," Eli told Peyton and 4th quarter guest Chris Long.

"I would give the bird, I don't know, can we do that?? I'm sure you can blur that out, right??"

As it turns out, E, -- no, you can't do that and no, they couldn't blur it out ... but that didn't stop him from holding up the gesture for a few solid…