How can i not unequip a tool but you can only switch tools?

How can i not unequip a tool but you can only switch tools? I can't really wrap my head around it. I didn't do the code when you switch tools. I only tested it for one tool but when i unequip the tool it lags then freezes. This is the error: ? Something unexpectedly tried to set the parent of FastCastGun to ProGamer(Character) while trying to set the parent of FastCastGun. Current parent is Backpack. (x2). This error keep repeating simultaneously with the lag. How can I fix it and how to make the script when you can only switch tools? This applies in many fps games.

Heres my code:

local animateequip = script.Parent.animationequip
local anim = script.Parent.Animation
local equipped = false
animateequip.OnServerEvent:Connect(function(player)
    equipped = true
    if equipped == true then
    local hum = player.Character.Humanoid
    local equip = hum:LoadAnimation(anim)
        equip:Play() -- is it the animation?
        end
    end)
local function characteradded(character)
    local hum = character.Humanoid
    print(character)
    hum:EquipTool(script.Parent)
    script.Parent.Unequipped:Connect(function()-- this one maybe
        equipped = false
        if equipped == false then
            equipped = true
            hum:EquipTool(script.Parent)
        end
    end)
end


local function playeradded(player)
    player.CharacterAdded:Connect(characteradded)
    local charact = player.Character
    if charact then
        characteradded(charact)
    end
end

game.Players.PlayerAdded:Connect(playeradded)

for i,v in pairs(game.Players:GetPlayers()) do
    playeradded(v)
end