breaks in two - going wild, bucking, trying to get the cowboy off its back
buck off - being thrown from the horse
jerk him sideways - pulling the reins to one side or the other will cause the horse to turn his head around, most horses will then slow down
stay loose - to relax in the saddle (how does one do that under these conditions is the joke here)
rake some fur - use your spurs to jab the horse's neck such as one sees in a rodeo
gut hooks - spurs
pullin' leather - refers to grabing the saddle horn to maintain your seat and ballance
grab your slack - take up the slack in the reins so as to have some control

If your pony breaks in two
There are certain things a fellah' needs to do
If you follow his advice right down to the letter
Your buck off average is bound to get better

Only problem is, you can't find two in a thousand of em' that'l tell you the same thing

There're those who'll tell ya it's in your seat
And the way a fellow holds his feet
You gota sit back a little and drop your heels
Try it one time son see how it feels

Others say the thing to do
Is jerk him sideways a time or two
Pull his head around to the left or the right
And break his momentum, he'll give up the fight

Oh yeah, don't forget to stay loose

Others say to rake some fur
Get agressive use your spurs
Just jab them gut hooks into his side
And bust him into a run it's easier to ride
Probably won't go through a fence
Stay relaxed now don't get tense
And if he happens to run you underneath a tree
Remember decapitation is preferable to a buck off, 'cus that can be embarrassing

Don't worry pard, I bet they can sew that ear back on

Some call it shameful to grab the horn
Others say there is no scorn
For those of us that have to go pullin' leather
Because stayin' aboard is always better
Problem is it happens way too fast
Ain't got a chance to grab your slack
Gives a grunt and he leaves the ground
N' farts you off n' drags you around

Hard to catch your breath when that happens

Thing is the guys that tell you this stuff
They kind of like it when things get rough
They say they don't want you to break your neck
But they do enjoy watchin' a good wreck
They been bucked off themselves a time or two
Ain't about to make it any easier for you
And the secret they're keepin to themselves of course
The best way to handle a snorty horse
Is to let some other idiot ride him

If you see your stirrups slap together above the saddle horn you're probably bucked off