From the official press release:

PLAYISM is proud to announce that DEEEER Simulator: Your Average Everyday Deer Game, the slow-life town destruction game by Gibier Games, will be collaborating with the anime My Deer Friend Nokotan with a new limited-time action, where selecting the “Dance” command in-game will let you do the Shikanoko Dance accompanied by the My Deer Friend Nokotan opening theme “Shikairo Days”.

The collaboration will take place from January 7 to March 31, 2025