UFC 4 | BJJ & JUDO Takedowns - Back Clinch (Guide in Description)
To get to back clinch = flick your left anolog stick to the direction of your opponents back when in cage single under.
(Example: your opponent is facing to the camera and their back is facing away push the anolog stick up)
To backpack your opponent from back clinch = press R1 + Square/Triangle
To takedown your opponent and have them in backsitting from backpack = press R1 + Cross/Circle
To choke your opponent from backpack = press R1 + Square/Triangle