Tiddygate2021 refers to a viral debate in the Dungeons & Dragons community about whether or not Lizardfolk, a species of bipedal human-like lizards, should have breasts or not. The debate largely took place on the /r/DnD and /r/DnDmemes subreddits throughout early 2021, where it was deemed "Tiddygate2021" on the latter and given its own post flair.

https://knowyourmeme.com/memes/tiddygate2021