This will explain how to perform the SPG glitches.
There are a few different methods, you'll just need to try which one works for the certain game.
1) Sign in to your SOURCE profile on controller #1.
*Do NOT sign in on controller #2.*
2) Start the game up.
You may or may not have to actually load the game (load the save for that particular game). It really depends on what game you are performing the glitch on as they vary.
3) Press the guide button on controller #2.
4) Press the X (blue button) on controller #2.
5) Put controller #2 down.
6) Sign in to the DESTINATION profile on controller ONE #1.
1) Sign into Source Profile on controller 1.
2) Load game up and go to the hotspot.
3) As the game's loading (or while at hotspot) press the guide button on controller 1 then press X to sign out.
4) After it signs you out, press X button again to sign in and choose the destination profile.
5) If done fast enough and right you should glitch now.
1) Sign into the source profile on controller 1.
2) Load the game and go to it's "hot spot".
3) Press the guide button on controller 2, then press X to sign in. Choose the Destination profile and as soon as you select it and press A (with controller 2) start pressing X & A buttons really fast on controller 1.
4) If done right your source profile (the one you just signed into on controller 2) should now be the profile on controller 1 (it switched).
Note: If one of these methods does not work, then it can't be done. It all depends on what game as to which glitch to use and when/where to perform it. And also there are a lot of games that the SPG only works on an unupdated (pre NXE) Xbox.
Credit Goes To JizzaBeez