Can you imagine the crazy ass abilities Katara had as a water bender? I'm not talking about fighting, I'm talking about sex.
Think about it, instant enema for her. She would be down for anal almost anytime of the day. Oh man, and the saliva play. I'm pretty sure it doesn't work like this, but can you imagine being lathered in her spit? She'll tongue box the inside of your mouth and work her magical sex organ down your chest and on to your dick. The saliva in her mouth would give your a whirlpool like blowjob if she really wanted to. It would be like having a rotating fleshlight with a tongue to make sure your dick is the cleanest it'll ever be.
On top of all that, when the full moon comes out, you best be ready for a mind numbing orgasm as she plays with the blood inside you're erected phallus, and contorts your dick in pleasurable ways that's physically and legally not possible. Katara could cumbend your spunk and give herself a full body bathe in it. The reason Aang looked so young during the avatar state was because he died in his mid-40's, blasting rope one last time in a seizure like orgasm on a full moon.
