Bakka is used as a slang term for the Norwegian high school Elvebakken (river hill). The school is know for its ritual sacrifices of goats, and their famous ball. Where they dress like lizards and greet each other by folding their hands over their chest. They then say “little Frey, little Frey and all the anthropologist”. Then they have a mass orgy.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.