Disclaimer: I don't own ATLA.
Of the entire group Sokka is the heaviest sleep. He's the type who can fall asleep anywhere and at any given time.
He himself loves to sleep. Every day he does his best to sleep in, but his plans are always foiled. He likes to use the excuse that he's a growing boy and he needs his rest so that he can grow big and strong. His comrades, particularly his sister, usually respond by dragging him out of his sleeping bag while explaining to him that he doesn't do anything during the day that requires excessive sleep.
This usual routine has become more like a distant memory. For Sokka has been sleeping very little these past few weeks. Instead of snoring and enjoying the blissful wonders of dreamland, he lies wide awake glaring at his sister's back. After all, it was really all her fault. He never wanted to get mixed up with the Fire Nation. Surely it was he who wanted to form cordial relations with their arch enemy and his female companions.
Cordial my ass. Instead of watching out for surprise attacks I now have to watch out for molestation.
Another little Sokka x Ty Lee moment. :)