Her pussy at least. And he gets a good laugh first.

"Alright then Aquarius," Natsu said, rubbing his hands together gleefully.

"...I don't like that look," she repeated.

"Go stand there, and bend over to put your hands on that wall," Natsu ordered, pointing.

"Yes... Master..." she grumbled, slowly standing... And then stumbling due to being completely unused to walking on feet, and flailed around, throwing her hands forward to catch herself... Which ended up right on the wall Natsu had ordered them to be on. Even clumsily, it seemed her body still obeyed orders, though her legs quivered.

Natsu, not having expected that, burst out laughing, and Lucy joined in. "Wow, she like, nearly face planted on the wall!" she giggled.

"Very funny," Aquarius grumbled, red with humiliation. Natsu smirked, and walked up behind her.

"Stay up, I know it's gonna be hard on untrained legs, especially with what's about to happen, but I will be enjoying you uninterrupted if you don't want to flip like a fish again."

"You... You said you wouldn't make me do that anymore!" she whined.

"No, I agreed to remove the part of this that made it automatic in the right conditions... Never said I'd never order it directly..." He then pressed into her from behind.

"Ah!" she cried out, as Natsu put his hands on her ass and started to pump, while she strained to stay standing despite it all. Both to follow orders, and to avoid having to suffer that indignity again.