Similar to phrases like oh my god or jesus christ, fuck-in-a-bucket is meant to be exlamatory or an adjective to describe someone particularly insane or eccentric.
When you make a trade that makes everyone else in the league say "Fucking A!" Phrase originally coined by Oakland A's GM Billy Beane. Applicable in any major league sport, fantasy sports, or to the average fan whose team makes a stupid, or savvy, trade.
KC Royals Idiot: "I just traded Johnny Damon to the A's for two no-name minor leaguers!"
Bill - Did you go to the concert last night?
John - Yeah, dude it was like a monkey fucking a football, the organizers better get their shit together next time.