Certain breeds are more prone to getting "Cresty". My mare needed 100 pounds put on her when I bought her 8 weeks ago. She's now at optimal weight, but her neck is a little more cresty than I'd like for our breed shows. So my trainer will be mixing up a concoction of alcohol and glycerin during the summer for our work outs, spraying it at the crest, and putting the neck sweat on her. After a couple months of doing this, the cresty neck will not be so apparent.
She's a Morgan by the way, one of the breeds that get cresty.
I was thinking Id spray some on my hips and wrap up in some plastic wrap while I ride, and by August, we'll both be less fatty for our show LOL