I just posted a dissertation on the R1-Forum on backing it in. Enjoy and let me know what you think!
Sliding The Rear 101:
Motorcycle racing, heck just riding, is a very rider specific thing. There are many ways to achieve the same results and the one that you are most comfortable with IS the right one for you. With that said these are the various means by which I slide the rear.
Method 1 (aka showing off):
a) apply front brake moderately
b) pull in clutch
c) apply rear brake until you feel chatter
d) with a strong hold on the bars begin to pivot the bike around your torso (taking weight off the footpegs helps immensely, i.e. support your body using just the bars)
e) rear end steps out and depending on direction you twisted your body either goes left or right
f) pull rear back in line
g) release rear brake
h) rev motor and let out clutch
Explanation: Front brake loads front wheel so you can more easily get the rear to lock up (duh); clutch disengaged allows you to control the amount of rear wheel lock with just the rear brake simplifying things.
Personal observations: Fun and easy to do but be careful not to release the front brake and rear simultaneously while bent out of shape. The sudden weight transfer to the rear while cocked side ways will have the bike buck you. You will probably not highside unless going very fast (70mph+), but it's still no fun and makes you look dumb. I don't use this method on the track for a couple of reasons. First on the track I am braking much harder and a simpler way of sliding the rear is available. Second this method has a great deal of the weight still on the rear tire. Trying to get the rear wheel pulled into line while increasing lean and simultaneously getting it to speed back up to the bike's speed is a nightmare and a recipe for highsiding. I use this method only while more or less straight up and down; aka showing off for the hotties in the convertible mustang.
Method 2 (aka stuff style):
a) apply front brake very very strongly
b) shift down gears and rev match accordingly
c) pivot bike slightly around your torso
d) rear end will step out
e) steer it into the apex
Explanation: The super loaded front end takes all the weight off the rear and makes it unnecessary to use the rear brake to break traction and get the rear sideways, just a strong countersteer is enough.
Personal Observations: I use this method to stuff people. Essentially you blow your brake markers and stand the bike on its nose. The idea is that you get on the inside of the other guy and swing the rear out to pick him up. You kill his line and his mid-corner speed. This allows you time to drag race him out of the corner, and since you are on the inside, you pretty much have control. Due to this the stuff style works best on tight, slow corners where acceleration out of the apex is paramount. I emphasis the need to rev match very well since with so little load on the rear, extra engine braking can turn your nice entry slide into a bars to the lock disaster as the rear end swings around more than you wanted.
Method 3 (aka dirt track style)
a) apply front brake strongly as you normally would at your best pace
b) downshift and rev match normally except for the last gear
c) do not rev match last gear but rather gradually feed the clutch out while you start to counter steer (do NOT pivot the bike here, just countersteer like you normally would with a fair amount of weight on the pegs)
d) rear end will step out and use the clutch to dial in as much slide as you want
e) steer it into the apex
Explanation: The loaded front end allows just a tad bit of traction at the rear wheel, traction that the engine braking can easily over power.
Personal Observations: Unlike the stuff style where your countersteer both affects your lean and your slide, this separates the two so you can play with the rear independently. If I need to slide into a fast corner, I use this method rather than the stuff method because it gives me greater control so I don't highside. This method helps me a lot if my bike is having problems hitting apexes on a particular corner but my set-up is good for the other 90% of the track.
As I said earlier, riding is very rider specific and I have my bikes set up so that they allow me to control the bike in these ways. Someone that jacks up the rear with a very front heavy bias will probably put himself on the ground backing his bike in the way I do. That rider has different techniques for sliding the rear that work best for him. What I wrote will work for most riders, but if your set-up is radical or your riding style is very particular, it may not work so well for you. Like someone else said, ride and play to learn.
EDIT: What I wrote applies to bikes that do NOT have slipper clutches of course. I have yet to track a slipper clutch equipped bike so I won't write about that, BUT if someone likes what I've written and wants to give me a slipper clutch for a 2004 GSX-R 750 so I can investigate...