Its amazing how experienced trainers learn new training tricks through their training sessions.
If you have a small dog (5lbs or under) this can work for you.
Training sit can be a great fun but if you have a small dog that seems to jump instead of sit, it can become frustrating.
If you are having a similar problem I have your solution . When asking your dog to sit try using a low coffee table. When you ask for sit (using tips from my sit blog ) ask for it under the table. When your dog wants to jump he is limited in space and will actually be forced to sit. Continue asking your dog to sit until they are consistent . Then start asking for sit out from under the table . If they jump again ask one more time if still jumping then move back under the table.
This little technique is a great way for people with little training to experience real results.
In some cases people use a wall where you ask for sit and the dog sits because there is no more room to go and they naturally sit.
The table is a similar trick.