How do I move a seat when I'm sitting in it?

I'm trying to move a seat when I sit in it. My script isn't working, and isn't giving me an error message.

The following script is supposed to make the seat move by .25 studs every half a second when the script detects a Humanoid is sitting in the seat. The script is inside a seat.

local debounce = false

while true do
	wait(.5)
	if script.Parent.Occupant == "Humanoid" then
		
		if debounce == false then
			debounce = true
			
			while true do
				wait(.5)
				script.Parent.Position = script.Parent.Position - Vector3.new(0,0,.25)
			end
			
		end	
	end
end