How to correct rocking back for a sit?

Abrams backs up when he sits about 70% of the time, and I have no idea why he does it. I also have no idea how to get him to STOP doing it. Today in class I was marking when he would give me his attention. I ended up with a dog that was staring at me...three feet away. Every time he'd shift his weight, he'd inch backwards. There was a few times he would look at me, step backwards, and then sit. And I know when I was working with him at home the other day he would quite literally take three steps backwards before he would sit.

I don't think I'm leaning or putting my weight forward to somehow cue him to back up, but then, I guess I never really thought about it, either? And I suppose when we train at home, he's typically a few steps back from me at all times.

Also, when we play fetch, he will run a few steps away and stop, go down into a creep, and stare at me to throw the toy, and if I wait he backs up a step or two to better catch the toy when I do throw it, so I'm not sure if maybe I've just inadvertently reinforced it there, so he applies that to other things?

Our basic obedience instructor recommended not giving him as much slack in his lead, so when he goes to back up to sit he can't and I can properly mark/reward correct sits. In theory, that sounded great. In practice, Abrams is like, "She told me to sit! I am sitting! I don't care that the leash is tight and my head is being pulled forward, I'm SITTING! She told me to sit, so I am! Screw the uncomfortableness of the situation!"

So I obviously need a new plan of attack.

When I train at home, he's never on lead. Which, I can certainly change if I need to in order to help shape some things, but I guess I never even thought about clipping a lead to him since we're in a secure environment and I don't want the lead to be a requirement for commands.

Train so his butt's in a corner and he can't back up? Only reward sits where he remains stationary, and ignore the rest? Any other ideas?

Lots of rear foot awareness, teach the kick back stand, and rework your sit by only rewarding for those good ones you see would be my suggestion.

I was working on that with my puppy tonight as matter of fact. I just used a nose target. To get him to tuck up. He can't rock back if he's moving forward to touch his nose to your hand.

Oh, some rear foot awareness was also something I wanted to ask about. I swear to God he doesn't understand he has back feet. He won't jump up onto things, he has to climb up. And when he swims, his butt sinks because he doesn't understand that he has back feet that have to paddle, too. His hind end awareness is God awful.

What would be some good exercises to teach him hind end awareness?

ETA: Oh, a nose target would also be a good idea.

Here is where Phelan is...
First luring through the ladder, then dropping treats between the ladder to slow him, and encourage rear foot awareness when he stumbles into the rails.
http://youtu.be/wIyLSGakgyk

Next once they go through a few times you want to start helping them back up and learn to raise their feet in a straight line, not swinging out.
http://youtu.be/mbA_8BJfAoc

Last, all the perch work. Eventually it can become rear foot 2o2o type of behavior(go around, come from behind, climb over and know to stop with the front off and rear on). Or having him back up an target. Also climbing up stairs backwards.
http://youtu.be/1H3pwjft1dw

Eta, I personally wouldn't remove a lure until the motor skills are consistent. If he's having trouble I would raise the nose with the closed palm lure (so puppy is actually pushing at your hand trying to get it) and try to prevent any rocking back behavior.

Awesome. Thanks so much! (And ZOMG, Phelan is freaking cute.)

What would you recommend using as a ladder? I don't have one. I *may* be able to see if the wooden ladder my dad built for our old treehouse is still laying around at my parent's house and lug it to my apartment - those rungs may not have enough space between them, though. Hmmmm. How hard would it be to put together a PVC thing like in your videos?

Looksy! http://members.peak.org/~helix/Agility/ladder.html

And thank you, we're having lots of fun!

This is SO Logan. I tried to do back-foot targeting with him and made NO progress over 3 weeks because he was all "BUT I HAVE NO BACK FEET!" Today he got all muddy, so he made sure to groom himself. He licked his front legs completely clean...and his back feet were still totally muddy o_0

HOWEVER, I recently got him a set of boots, and when his boots are on he seems to realize he has feet back there. So I'm going to attempt to use that to my advantage.

It took Backup forever to learn how to manipulate his rear end, it was a long and frustrating road, but repetition and variety in exercises really did help.

I'm also starting a "place" or "guard" position with Phelan which will be heeling between my legs, fwd & back. It can actually help force them to learn how to step directly back instead of the typical swinging out which dogs then to do naturally.

This video is noisy and you'll see out issues but here I am fooling with Sloan's reverse and then transferring it to her heel to work on backing up without guide(my legs). If the dog already has a heel you can practice this against a wall (which is what I spent hours trying with B) but between the legs somehow helps dogs not shut down, sit, watch you over their shoulder, and think "nope, that's impossible".

http://youtu.be/Unu3x0jA-to

Phelan is pretty much the cutest thing ever. Abrams would be too, but no vid. Wesley had no idea his rear legs existed until I shaped him (ever so slowly) to back up. It was like a switch turned on, now he backs up all the time. Like when we're at the beach, he'll run toward the water and back up when a wave comes in. Very amusing to see how much he uses it now that he knows!