I have a 5 month old lab/shepard mix. She is spayed and even house broken. She sits, lies, and shakes my hand but for some reason when I put her leash on her she acts as though I'm trying to kill her and does the death roll to try to get it off. Not only is this annoying but also embarrassing. I have tried the treats, praises, and all, and I am at a loss. PLEASE HELP!

I have had quite a few pups who think the lead is trying to kill them. The key is just to be patient, the penny will drop eventually and they will get used to it.

Does she have a problem with wearing a collar at all or is it just the lead?
If she doesn't like the sensation of something around her neck you could look at getting a harness or a gentle leader for her.
Harnesses strap on around the dogs withers and around the chest. The lead then clips on at the base of the dogs neck.

Gentle leaders look a bit like a muzzle or a horses bridle and the lead clips onto what is essentially the side of the dogs face.

Here's a photo of my little feral during his lead training. I coaxed him along by putting just a bit of pressure on the lead and offering treats in front of him. It took a while but he eventually caught on.

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We got our puppy used to it by leaving the collar and leash on him around the house so he could drag it around and get used to the weight of it. He got used to it pretty quickly. I am curious what type of collar you are using? If you are using a choke collar I would try a regular collar instead.

Just put a leash on her, in the house and let her walk around with it, or put it on her and hang onto it and just sit down in a spot with her, so she won't feel like she's being pulled around or anything, you have to get her used to it. Then she will come around.