Rectumnal
The twice yearly periods, roughly corresponding to the spring and fall equinox, each lasting approximately 30 days, when it is socially acceptable to be an absolute, overt asshole towards other people, deflecting all responsibility for one's poor behavior, and instead blaming one's extreme anti-social behavior and absolute, fucking social retardation on the alignment of the planets, celestial mechanics, changing of the seasons, and anything else plausibly related to the lunar tides.
