I attached a pole inside a coffee can filled with cement to stabilize it and can now use it in various activities. This video shows how I use it for a reacgubg abd insertion activity while on the horse. I cut away the bottom of a gallon water jug and slipped it onto the pole through the spout. The yellow swimming noodle covering the pole below it helps to keep it in place.
This girl in the video is facing backwards. I can vary the challenge by placing the pole/bottle in different locations or have her face sideways reaching to the sides or behind her (great for trunk rotation). Varying the pole's height also allows the therapist to individualize the activity. I can require her to post to reach for the balls while facing forwards or even use the activity while kneeling or dropping them in the holder while standing on top of the horse.
I think that therapists may find this activity useful working with children while on a trampoline or other land based movement apparati. Present the balls to the child's right hand to place in the holder positioned left of the trampoline and then reverse to move left to right. After some success have the child jump ( I like having them count to ten or recite the alphabet so that there is an end) and then stop to do the ball placement activity again. Of course, you can do this same activity tossing balls into large boxes-working on different skills.