noun
head of the table; seat of honor
Colloquial term for the most honored seat at a gathering, often used humorously or affectionately for the guest of honor, especially at birthday parties.
今日は君が主役だから、お誕生日席に座ってね。
You're the star today, so take the seat of honor.
お誕生日席に座らされて、ちょっと照れくさかった。
I was made to sit at the head of the table and felt a bit embarrassed.
上座 is the standard, formal term for the seat of honor, while お誕生日席 is a colloquial, playful variant often associated with birthday celebrations.
Compound of お (honorific prefix) + 誕生日 (birthday) + 席 (seat). The exact origin is uncertain, but it likely arose as a lighthearted way to refer to the seat of honor at birthday parties.