Not sure what fluid I need?

[ZachDDill]

Well the rear master would leak brake fluid. But I can't recall hearing someone having issues with a leaky rear master. A leaking clutch slave... oh yeah.

If you're sure it's brake fluid I personally would start my looking at the clutch system.

Clutch is my first thing to look at, I was tracing the cables trying to figure out how it all worked and what leads to what and how I could possible fix it.

[battlecry]

If the spill is on the right hand side of the bike, check the rear master at the banjo bolt.
If it is oil and not brake fluid, check for a split crankcase vent housing.

You can coat the bike in talcum powder and go for a ride.  It sometimes helps in finding leaks. 
 

[Slide Panda]

Relatively simple. The clutch master is connected to the slave via a braided steel line that runs down the left side of the bike. The slave can be seen in the right of the photo you posted. Under normal conditions, it's a sealed system save for the reservoir on your handle bars. When you squeeze the level it pumps fluid from the master down the line into the slave, which pushes a piston.

There's an o-ring seal on that piston that is the most common point of failure. Good news is it can be replaced - bad it that it's usually a messy pain in the ass to do so. Many folks have opted over the years just to replace the slave instead. There's a big market for slaves on the dry clutch bikes (won't go into that here) but you'll probably want to focus on an stock replacement - if you need to.

Though that seal is a common point of failure there's a couple spots to check as well. Make sure that both the banjo and bleeder of the banjo bleeder on the clutch slave are tightened sufficiently and not allowing fluid to leak. Though it's uncommon, leaks can develop there.

Either way - clean up the area well. Brake fluid will wash off with water. Wash and dry the area. If you really want to check, pull off the clutch slave by removing the 3 bolts that hold it on and wipe down the interior with a damp cloth. - (THough if you find it's all wet in there with your mystery fluid, you've probably found the leak) Once clean and dry - put everything back. While you're letting your wash work dry, go to the pharmacy and buy some spray powder deodorant like Arid.

After you've made sure it's all dry, put the slave back on and spray some of the powder around where the slave meets the case and any other area you might suspect as the leak source and go for a little ride. The powder will change color quickly when damp and will make it easier to center on the leak.