assbackwards

assbackwards or ass·back·ward [as-bak-werdz] Word Origin adverb Slang: Sometimes Vulgar.

1. in an order or way reverse from the usual: You’ve sewn the sleeve on assbackwards.
2. in a manner incongruously or preposterously counter to what is customary, probable, or feasible: The plan fell apart because everything leading up to it was handled assbackwards.

Origin of assbackwards First recorded in 1935–40; ass2 + backwards