its annoying me that unity wont let me call a GUI Button function in an OnTriggerEnter function after the if statement. I want to make instructions come up when you enter a trigger, but unity tells me that the I can only call GUI functions from inside OnGUI(). any ideas around this?

heres the script so far:

var tips1 : GUIText;
var tipsPREFAB : GUIText;

function OnTriggerEnter (player : Collider) 
{
    if(player.gameObject.name == "BlueMan")
    {
       OnGUI();
    }
}

function OnGUI () 
{
    (GUI.Button (Rect(10, 300, 100, 80), "press T for help "));
}