"Okay." He closes his eyes, visible through the mask, and after about a minute or so starts moving his fingers.

And he raises his arm.

Puppeteer lowers a finger, raises another.

Other arm.

He lowers his fingers. "Seems to work."

Nod. "Now - I swear that until I say 'escape clause' or one hour has passed I will not take any actions I did not decide on in advance -"

Raise finger.

Still works.

He lowers his finger again. "My power works by taking direct control of your nervous system, so I believe it doesn't count as you having done it."

He can't move!

"- escape clause - yeah, that'd make sense."

"An application that might be... a bit more dangerous to you is making you swear something, if that's binding as it seems to be."

"It is. You can make people say things?"

"Yes. I can control any of your muscles. Some are more complex than others, but I can."

"I don't know if it'd count as swearing, for the same reason it doesn't count as moving, but we should check - something like 'until an hour has passed or I say 'escape clause' I swear not to say the word 'elephant' -"

He nods. "This will take a few more minutes, I need to get a better feel for how your nervous system works..."

He wraps his wings around himself and waits.

"...your wings feel very peculiar. And your whole nervous system is... subtly different. I expect that's because of the physical alterations due to your trigger event?"

"...yeah, probably." 

"Were there any other physical alterations than the obvious ones?" he asks, making Fëanáro's wings and ears tingle very slightly.

"...I can control my heartrate and stuff by thinking about it? ...actually I should check if I can control my nerves directly too, I haven't tried that yet."

"Fascinating. And I think I got a bead on your speech muscles."

"Okay. Try the oath thing first, then we can see what happens if I try the body control thing."

He moves his fingers again, and Fëanáro finds himself saying the oath. It feels very strange, his muscles move in weird ways that don't quite hurt but aren't natural, either, and it sounds a bit slurred but perfectly comprehensible.

And it counts, relevantly. "That worked. Escape clause."

"Interesting. I wonder why that worked to create an oath when there was no intention but the intention was relevant for raising your arm."