Trying to fix something that so completely fucked up that when you're done, its no longer FUCKED UP, but FEXED UP. A combination of FUCKED UP, and FIXED UP.
It's the end result when a (much) older woman has sex with a younger lad, with tasty results. When the moment of truth comes, it's time for him to Feed Nana!
The phrase is known to have a compound meaning but this is the most widely accepted. It is believed to have originated from Alt-Right podcaster Anthony Cumia just before he was permanently suspended from Twitter in 2018.