Quote Originally Posted by tz1
an easy way is by using your thumb and index finger in the shape of a check mark, and run it down it's spine. when u reach their bottom , push down easily, and since it's a spot which enables you to make them sit easy, they should sit. and when they do, say "Sit!"
The problem with that method is when you push their butt down they "fight back" and push up. You're stronger, so you'll win and his butt will go down, but it's against their reflexes which are telling them to go up. It's like if someone pushes your shoulders back you don't just fall to the floor, your reflexes kick in and push forward so that you don't fall.

I taught my dogs to sit the way _Sassy_ suggested. My dogs picked it up really quickly.