DaiSuga

DaiSuga is the slash ship between Daichi Suwamura and Koushi Sugawara from the Haikyu!! fandom.

Canon
Daichi and Suga are both members of the Karasuno high school volleyball club. They have a lot of canon factors, making them a strong pair. Firstly, they're both 3rd years and also in the same class, Class 4. Secondly, Daichi's the captain while Suga's the vice-captain. Thirdly, Daichi's a wing spiker and Suga's a setter, making them have the setter/hitter relationship. In addition, Daichi's jersey is No 1 and Suga's jersey is No 2.

Throughout the series, these two have a strong friendship, off and on the court. Their personalities are quite similar, both being friendly, kind and also firm when their underclassmen are misbehaving.

At the start of Episode 21, when Suga's subbed in for Kageyama, Suga tells Daichi to speak up more, as he's been quiet from the start. This shocks Tanaka and Asahi, as they both think that Suga's the only one who can lecture Daichi. This shows that they have a strong bond with each other. Although they don't have a lot of events together, they help their team become stronger, being the sturdy foundation.

Fanon
DaiSuga is the most popular ship for both characters. In most fanwork, these two are often referred to as the parents of Karasuno: Dadchi and Sugamama. They're often shown with the rest of Karasuno, trying to control the team/crows. In other fanworks, they're shown to be happy and caring towards each other.

According to AO3, DaiSuga is the 4th most popular ship in Haikyu!!

Dominance portrayal

Although DaiSuga isn't seen as a sexual ship, there have been fics where Daichi would take the lead. This is mainly because of his personality being strong and firm. Also as the team captain of a team with some troubling underclassmen, his nature would be seen like this. As for Suga, he's personality is more on the light and gentle side. But overall, their ship is healthy and seen as "fluffy".

Fandom
TUMBLR
 * Daichi/Sugawara tag on AO3
 * Daichi/Sugawara tag on AO3