I just made a topic on this. Basically something to put between my pocket and my phone. Sony PSP Soft Case, works perfect with the bumper: http://www.amazon.com/gp/product/B00B8WPEE6/
I use a PSP soft case and it fits perfect.
Sony PSP System Pouch https://www.amazon.com/dp/B00B8WPEE6/ref=cm_sw_r_cp_api_glt_fabc_0XP8YZP04D5NQTQSH3M3