“Sometimes being a brother is even better than being a superhero.”
Based on this gif right here and this comment about how Mako doesn’t use his hands to climb up there like Bolin.
I can just imagine some whispered background dialogue between them.
“You okay, Bolin?”
“Well I’m right here and don’t forget to—”
“It’s okay, Mako. I got this.”
“Okay…. But I’m here in case you get tired—”
“Mako. Please stop.”