Like, seriously. So square.
So Square dance is a Uncommon Fortnite Emote. This emote is one of the Battle Pass cosmetics in Chapter 2 Season 3. You can get it once you have reached Tier 33.
The gesture So Square belongs to Chapter 2 Season 3. Thia gesture is available as a reward by unlocking Level 33 of Battle Pass from Chapter 2 Season 3.