iduzbad:

The Bully-Thranduil-Day has been established as a national dwarven bank
holiday shortly after Thorin was crowned King under the Mountain. The official khuzdul name for the day is o’lij which literally translates to ‘the art of cheek’. The
date varies, depending on when the dwarves feel most festive, but it
usually happens shortly after the beginning of spring to mock Thranduil’s crown blossoming again – an equivalent to an infant dwarf growing a first bum fluff.

Culinary delights include roasted stag, and thin wine that they generously refer to as ‘grape juice’. Traditionally the halls of Erebor are decorated with branches and brambles, and the children paint incredibly thick caterpillar eyebrows on each other and try to scare the grown-ups. They also come knocking on doors yelling “GEMS OR WAR!”.

It is Thorin’s favourite holiday, right after Durin’s Day.