Do you guide her with your legs to and over the jump? There is no harm in using a light bump with each stride up to the jump to keep her moving, paired with a cluck with each bump. About 5 strides to the jump usually helps. I'd only try this if you have the coordination to post, bump, cluck, steer, and go into two point at the right time.
If that still doesn't help, there is no harm in using a crop... sometimes a horse will be more likely to do what you ask if it knows you have one, sometimes you don't even have to use it. If you DO, use it only as much as you need to get the desired effect, as a reinforcement of your leg.
Owner and head trainer of SE-Wisconsin Horse Care
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