Phyxius:

Maybe it's like the bend and snap.

Oh, I thought it was maybe a reference to the "Texas Dip", although I still don't understand how that relates to hitting a jump! 

 Oh, Okay. When you said bend and snap, I knew exactly what you ment. I just watched that day before yesterday. How funny. Thanks

fedex.:

Maybe they're referring to your position. I can see the "slide" as a crest release. The bow? Closing your hip angle, I suppose. I think I'm on the right track here.

Sorry i guess i should have explained what the 'slide and bow' is

It is when you lean fowards elbows and knukles on the horses neck and your bum doesnt come out of the saddle

 Oh, okay. I understand now. That's a good tip. I will definetely practice that. Thanks

 Ok, now I'm confused. I have seen riders do both. It does make more sense to lift your bum out of the seat so you're not interfearing with the horse.

 Thanks for the tip. The horse in the photo looks like he has to try harder to get up over the fence. 

 I do notice in a couple of pics that my dad took, I am sitting over the jump. In others I don't. I just need to practice more. Thanks.

 Thanks.

agreed -- you do NOT want your butt in the saddle, it should be just above.  Also, your elbows should not be touching your horse's neck, only a light pressure from your hands to support your upper body in your crest release.