This was a prompt given to me by one of my tumblr friends. I also decided to use an image I had on my phone as inspiration on this fic too. It's more so a drabble than anything, but I thought I'd share this nonetheless.
"Ugh! I'm tired of hearing you complain! What's the big deal?"
"You're my baby sister! I don't want to hear or see you doing stuff with Aang." Sokka complained as he argued with Katara. He approved of their relationship, but he preferred them to keep it to themselves.
"How is that fair? I never complain when you and Suki do things in front of us! How are we any different?"
"You two are younger! You haven't hit marrying age yet and you're getting mad at me about displays of affection?"
"I turn 16 in a few months Sokka! I will be of marrying age pretty soon! Besides, we saved the world! We were young when that happened, so are you saying I'm not mature enough for a relationship?"
He sighed. "That's not what I'm saying Katara. What I'm saying is I'd rather not come home and see you two sucking each others face. I like coming home knowing your doing something other than being all mushy with Aang."
Katara growled at her brother. It didn't make any sense to her! He did everything, even more than they ever have, and yet he's complaining that they're being affectionate. She would never understand her brother and his ideas.
Aang watched silently as the two siblings bickered. It wasn't anything new as they constantly did this since the end of the war. He couldn't keep his face from turning red at the conversation though. He didn't expect Sokka to see them in that position, with her straddling his legs while they made out. At this point, he wasn't sure what to say, so he remained silent.
"I'm almost sixteen Sokka! You can't keep complaining about me and Aang. There's nothing wrong with us being happy!"
"I never said that! I just prefer if you keep your oogies to yourself. If dad had caught you in that position-"
"Dad would not be flipping off right now. Yes, it'd be really awkward, but he wouldn't lecture me the way you are at the moment. Dad trusts Aang. Why don't you?"
"It's not that I don't trust Aang or you. It's that I don't trust you two together. Alone. I've been at your stage Katara, I know what you two are feeling right now. And I don't want you to do something you'll regret later on."
Her fists were clenched as she glared at her brother. Why was it so hard for him to just leave them alone? They never interfered with his relationship, so what gave him any rights? Suddenly, an idea popped into her head.
"I'm tired of hearing you complain Sokka. This is between me and Aang and what you say doesn't matter!'
With that, she yanked on Aang's robe and pulled him into a heated kiss, causing Sokka to scream and Aang to blush madly. He was in complete shock at Katara's actions but despite hearing the yelling from a scarred Sokka, he complied and returned the kiss with just as much passion as Katara.
They were wrapped in each other, feeling the other with their hands and not even paying attention to Sokka's face as it turned from red, to purple, to red in anger and shock. He was completely scarred and he couldn't do a thing about it.
"OOGIES!" He yelled before running away from the couple, completely scarred and horrified at their actions. Never again would he look at the two the same.