So according to Tiny Cartridge, hidden away on the many cheats available in Shovel Knight is "Butt Mode". Just type in "WSWWAEAW" as you name at the start of the game. This will replace several words that are used in the game with "Butt".

What a fun urazawa!(◐ o ◑ )

*OMAKE* After I posted here, it got to Kotaku main so here is butt video fun!