In UFC Undisputed 3 for the PS3 and Xbox 360, forcing someone to tap out (aka submit) is a lot different that you’re used to in previous games.
To start a submission, you need to be in the right position on the ground. You can change your position on your opponent by using the right analog stick.
Once you have your opponent in the position you want, you click down on the right analog stick to start a submission.
Once you do this, it starts the submission mini game. An octagon shape will come up, and you essentially chase your opponent around the octagon and try to cover up their color as long as possible until you fill the green bar. If you can fill the green bar when time runs out, then your opponent taps out, if not then they escape or perform a reverse depending on how well or poorly you did in the mini game.