Roll Over
This is a fun trick. Sometimes my dog is so excited that she tries to roll over while sitting, it is hilarious. Before starting to train your dog to roll over, you need to have already taught them to lay down on command.
How to teach your dog to roll over
After your dog is laying down give the command to "Roll Over". As you say this, you can gentle 'help' them roll over with your hands. Once they make a complete roll, give them praise. Repeat and practice until your dog is rolling over with only the verbal command.
If your dog doesn't like to be 'helped' to roll over, you shouldn't force them too much if you pushing on them is freaking the dog out. Instead, take the time to play with your dog. Wrestle with them until they are comfortable with your hands pushing and pulling their body.
Another method is to have a friend help you out. You say "Roll Over" and your friend helps your dog do the motions.
Finally, for a few dogs I have known, the following technique was all that was needed: From the laying down position say "Roll Over" as you do motion your hand(which is holding a treat) in a circle imitating the rolling over motion.
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