I want an event to occur when my gameobject is in a collider, and a button was pressed?

Right now I have this:

Code (CSharp):

1.  private void OnTriggerStay(Collider collider)
2. {
3.      if (collider.gameObject.tag == "Pickup" && buttonPress == true)
4.      {
5.          GameObject spawnNeutral = (GameObject)Instantiate(neutral, transform.position, transform.rotation);
6.      }
7. }
8. public void SpawnButton()
9. {
10.      buttonPress = true;
11. }

However once the button is pressed, then the gameobject can enter the trigger whenever and it will work. I only want it to work when it is inside the trigger.

 

Code (CSharp):

1. bool allowButtonPress = false;
2.  
3. private void OnTriggerStay(Collider collider)
4. {
5.      allowButtonPress = true;
6.      if (collider.gameObject.tag == "Pickup" && buttonPress == true)
7.      {
8.          GameObject spawnNeutral = (GameObject)Instantiate(neutral, transform.position, transform.rotation);
9.          buttonPress = false; // i assume you should reset the button press here
10.      }
11. }
12.  
13. private void OnTriggerExit(Collider collider)
14. {
15.      allowButtonPress = false;
16. }
17.  
18.  
19. public void SpawnButton()
20. {
21.    if (allowButtonPress) buttonPress = true;
22. }