Dead ass

shuu have droopy eyes and yuu has normal eyes

The way to tell them apart for me was to focus on their hair. Yuusei had his hair swooped to the right (left if you consider irl perspective) and Shuusei had his to the left (opposite irl perspective).That’s like the only way I could tell them apart though lol. Paying attention to the placement of their earrings can also help.

I see their hair and eyes like those two up there. But the easiest is to look at their piercings. Yuusei has his piercing on the left and Shuusei has his on the right.

Shuu has droopy eyes and slightly meaner looking face. He also has a right earring and addresses him as “Yoshi”

Yuu has a cheerful face, a left earring addresses him as “Haru”