Can't get pony to canter. Any advice?

All horses know how to canter. Ponies are especially brilliant at figuring out how to get out of work. Use a crop behind your leg and lots of persistence to get it the first times and while cantering, HEAP on the praise and give her a nice long break just after carrying you along while cantering so she knows she did something amazing. Don't reward a few steps and a halt, only reward a forward flowing canter and you will be flying along in no time.

Also, I do like to use a verbal canter cue with horses starting out. It clears up any confusion on their part and is a great transition aid from the ground to undersaddle work. Yes, you don't want to rely on them forever, but clarity for a learning horse is a good thing.

Also, do check the footing where you are. If it is at all slick or unsafe, a smart pony will refuse cantering. Also, if they are unwell or hurt, they will refuse cantering. Those are about the only two things to clear up in your mind that really are a good "excuse" for not cantering.

Stay in the round pen for a while and teach the verbal command Canter, while you're using your whip and pressure from your body position. It might take 10 more sessions or more, but use a loud verbal command: cluck cluck cluck "CANTER!" over and over until it starts to sink in.

This will really help you transition over to saddle training it.

Once she's cantering in the round pen on command it will be easy as pie to take it to the saddle. Just when you cue in the saddle, use ONLY the outside leg behind the girth, don't squeeze with both legs. Do your cluck-cluck-cluck CANTER and use the outside leg behind the girth, this will tell that outside rear leg to fire specifically, so she'll learn leads from the very beginning.

Remember, you're not teaching her to canter. In her mind she doesn't have a gait called canter, she has Right Lead and Left Lead, so be sure you're speaking her language!

Ohhh the typical "I don't want to do it so I'll just act like I don't know what I'm doing"

A horse does not simply not know how to canter. All the gaits come completely naturally, it has nothing to do with she doesn't know how.

Pressure is the only way to get her to do it, when you pressure a horse they feel they have to do it in order to get away from it. Lunge her, and even if it takes all day, pressure her hard by slapping the lunge whip right behind her hind legs.

But, if you don't mind a temper tantrum, use a crop, and kick. Crops are not abusive, you can hit as many or as hard as you need to. It's a tool used for stubborn horses who don't do what they're told.

To hold the crop, hold it in between the reins and your hand, place the top of the crop in between your pointer finger and your thumb and the bottom between your pinky and your fourth finger. It may feel uncomfortable, but you'll get used to it. Start with lightly tapping, then slap her on the butt.

I'm afraid it's time to put the horse down.