Soon enough other needs manifested themselves : she had to pee. But first she had to give back a little to the city from which she took so much. She got up, letting her cockring slide off her soft flesh, and headed towards the water tower she had seen on her way to the airport. Tearing the top, she bent over and drank the water to wash down her meal and clench her thirst.

Getting back up, she made an apologetic expression. "I'm so sorry", she said out loud,  "all this taking and I haven't given you a gift. I can be so inconsiderate sometime. Here's a little something for you guys." That being said, she reopened the plane and poured its contents inside the water tower. "I heard sperm was really good, it's full of protein and minerals -- and now you'll be able to get plenty in your daily diets. Maybe this will help you get a bit stronger!" She was visibly enjoying tormenting them. She loved to think about the fact that even after she was gone, as the remaining survivors would try to go back to a normal life, they would be forced to drink her cum. Heck, they were so small that it would probably take months or years, the taste getting stronger with time. Their water would be tainted by her taste for years. Children born after her visit wouldn't know fresh water didn't taste like her seed and she loved the idea of having such a big impact while having her fun.

 
"You know, I never had so much fun helping people out. Giving can be so satisfying, espcially when it comes from yourself. At first I was thinking to go piss in the river next to your city, but that would just be waste and no one would be able to enjoy it. Instead, we'll enjoy it together!" she said in an uplifting voice.
Tresdin surveyed the town for a good place where her gift would not go to waste. She spotted a good container nearby, a stadium filled with people watching a game. Blocking the exits to avoid any leakage, she ripped off the roof. 
"Hey everyone! I'm sorry to disturb you guys during your game, but I brought drinks. It really can't wait any longer, to just take a break while I serve everyone."

Smiling at the crowd below, she grabbed her penis, aimed it at the bowl and let her urine flow. The feeling of release sent tingles in her spine, she closed her eyes and threw her head back. She let her body relax as her bladder emptied. Almost done, she looked back down and saw that the stadium was almost filled, most people were swimming or on the sides. She bent over, looking at the people. When she was done, the container was slightly overflowing, some of the liquid going in the streets "See, now everyone can drink to their heart's content." She took a deep breath, and sure enough the smell of piss filled her nose. It didn't bother her much, but she imagined it was disgusting to them. They were trying really hard to stay afloat, but they would only get progressively weaker and drown one by one, the outside world unable to help them.

Tormenting them was irresistible. "You know, you guys aren't even enjoying what I'm giving you. My body worked hard to produce all that. If you haven't noticed, some of you are starting to drown, and the others aren't even trying to help them. You should try drinking some, if you all work together you might lower the level enough to stand somewhere. Besides, it's not like you have a choice." She looked at them, keeping a serious look. Slowly, more and more people seriously considered her idea. Realizing they didn't have much of a choice, they started chugging the warm liquid down. "There you go, you can do it!" she encouraged. "Some of you aren't helping though, and that's a bit unfair. Here, I'll make sure everyone does their best." She spotted a young man who refused to drink her piss and pushed him down with her index finger, holding him underwater. If he was trying to fight her, she couldn't even feel it. She waited a good minute until she saw his body slowly go down to the bottom of the stadium.

Everyone was drinking her piss now, but they weren't making any visible progress. "You're all working so hard, I would feel bad if I didn't give it my all as well" she taunted. She grabbed her cock and pushed out a little more, shaking and squeezing her dick to let out every last drop. Of course, no one would be able to drink  gallons of liquid in a day, so they obviously wouldn't be able to do it in the next hour or two, but she liked how hard they tried. "I have other things to do, but I'll come back in a few hours to see your progress. Keep up the good work until then."

With that, she left. It was getting dark, and she was feeling tired. She would check on them in the morning, even though she knew what she would find. She walked a bit to a residential area, where she slowly laid down. Sitting down, she felt the crumbling houses under her butt, too lazy to give a thought about the people inside them. Laying down on her back she stretched, uncaring of the destruction she caused, until she settled with her hands behind her head, closing her eyes. She fell asleep quickly, her body spent from her battleg and satisfied from the fucking. Her body needed to repair itself now, using the thousands of people in her belly as material.