ContextActionService firing twice?

[quebecwhat]

function aimdown()
     print("yes")
end
cas:BindAction("onaimdown", aimdown, false, Enum.KeyCode.Q)

why is this firing twice?

[xDuosion]

Your problem is that it’s firing aimdown for the press starting and the press ending.
The below code fixes that.

local cas = game:GetService("ContextActionService")
function aimdown(actionName, inputState, inputObj)
    if inputState == Enum.UserInputState.Begin then
        print("yes")
    end
end
cas:BindAction("onaimdown", aimdown, false, Enum.KeyCode.Q)