If you're going to bring your own toilet paper, be sure its *single ply* toilet paper approved for septic systems. You can find it at RV stores if no where else.
The toilet paper you put in there needs to be the kind that will dissolve and not clog up the suction hose when the potties get emptied.
The JoS crew does *NOT* like reaching into the hose to dislodge whatever spurrious junk you dumped in a pottie. Spurrious junk includes baby wipes, paper seat protectors, condoms, the strange underwear you found in your tent, etc.
Another note, if you're female, pack along a ziploc bag for any special items you need to dispose of. The ziploc needs to be carried back to your camp and packed out. Under no circumstances should you be putting used pads or tampons in the potties. (or ziploc bags).
Yes, its gross, but its grosser still for the person that has to either pick that stuff out of the hose on site, or pick that stuff out of the screens at the disposal site.
Oh, and another 'if you're female'...
There have been a number of potties where I have been exceedingly thankful I don't need to sit down to pee.