How do I create a "magic shield"?

I want to create this shield that always appears in front of the player's torso, but I don't know how to always make it go a few studs away from the front of the player's torso.

Here's what I got :

local plr = script.Parent.Parent.Parent
local char = plr.Character or plr.CharacterAdded:Wait()
local p = Instance.new("Part",game.Workspace)
active = false
script.Parent.MouseButton1Click:Connect(function()
    	if char and not active then
    		local torso = char:WaitForChild("Torso")
    		active = true
    		p.Position = Vector3.new(torso.Position.X + 5,torso.Position.Y,torso.Position.Z)
    		p.Anchored = true
    		p.Size = Vector3.new(5,10,1)
    		p.Transparency = .7
    		p.Material = Enum.Material.Neon
    		wait(10)
    		p:Destroy()
    		wait(12)
    		active = false
    	end
    end)