Is there a way to skip over a while true do function while it plays in the background?

I am trying to address a body velocity in my script while having a while true do function play on it but i am having no luck finding out how to do so.

here's what i have

local b = Instance.new("BodyVelocity")
	b.Parent = v
	b.MaxForce = Vector3.new(1e8,1e8,1e8)
	b.Velocity = char.HumanoidRootPart.CFrame.lookVector*155
	wait(0.5)
	cast = true
	while cast == true do
	b.Velocity = mouse.Hit.lookVector*155
	wait(0.5)
end

ive tried putting the cast == true do function at the end but it cant reference b then and ive tried using another script and adding it to the body velocity but then it cant reference the player/mouse