I've been asked this a couple of times now, so I thought I'd set up a thread which tries to explain with pictures...
(Perhaps a mod might like to make it a sticky)
The PCC stands for Personal Charging Case.
It's a metal case, a little like a cigarette packet that charges your Titan (or Super) whilst it's in the case.
It will charge your battery from flat around 3 or 4 times, maybe even 5 if you're lucky. Then you must recharge the internal battery before use once more.
You split the e-cig in half because the charging points are in the screw-thread and you just take the two pieces out and screw them back together to use it.
It won't hold a complete one - But then that does help protect against inadvertant activation of your atomiser.
This also means that the juice will drain toward the atomiser side of the wadding whilst in the PCC, as you may have discovered, the Titan is so thirsty that it has a tendancy to dry off the top of the wadding (the atomiser-side) quicker than the wadding can wick it through. The orientation of the cartridge on the atomiser in the PCC is such that the liquid moves toward the atomiser giving you a good strong vape the next time you take it out and use it.

Open PCC whilst empty. Inside view.
From left to right. Cartridge slot 1 . Atomiser slot. Cartridge slot 2. Battery slot.
(the little piece of foam in the lid is a personal mod to help my batteries make good contact - I also charge a Super battery in here and I wanted to make sure that all of my batteries fit properly)

Open PCC whilst full.
Cartridge 1. Atomiser and cartridge. Cartridge 2. Battery.

Open PCC with contents hanging out for clarity.

Closed PCC charging the Titan battery.
As the battery reaches full charge, this light will flash.
The longer that the light spends OFF, the nearer it is to being fully charged.
Once the battery is fully charged, this light will remain OFF.

Mini USB port on bottom of PCC.

PCC charging on USB and charging Titan battery at the same time.

Middle light shows red - PCC needs charging.

Bottom light shows green - PCC fully charged.
Paul..
The RoadRunner..