I would like to hold the slenderer one in my arms, (15)
Who wouldn't want to hug that beautiful little black-and-white pony with the mane falling wild across her forehead? Yet the speaker doesn't actually follow through on this impulse ("would like"). Something is holding the speaker back. Is it fear of spooking the pony? Or fear of letting go emotionally? For whatever reason, the speaker does not take this step to bridge the separation from the world of nature.
Suddenly I realizeThat if I stepped out of my body I would break (23)
Notice the conditional tense of this statement ("if"). Again, something is holding the speaker back, and there's a hint of fear in the words "I would break." For the speaker, contact with the ponies seems to have triggered awareness of a spiritual dimension of nature, a unifying energy that transcends the physical world. But the speaker is not yet ready to step "out of my body," to accept the reality of a spiritual dimension that would end the speaker's isolation once and for all.