The tail symbolizes the completion of a spiritual action, the finishing touches. It brings our involvement to an end.
Psychological / Emotional Perspective:
The tail is necessary to the animal for balance, and thus in dreams can be recognized as a means of adjustment in difficult circumstances.
Everyday Material Aspects:
To dream of a tail can signify some residue from the past, something we still carry with us. Just as our tailbone (coccyx) can be vulnerable to injury, so we also can be affected by the past.
Gender / Specific Meanings:
In a man’s dream the tail can indicate sexual excitement, or possibly, by association, the penis. For a woman it will initially suggest her own basic energy, and perhaps later on her way of linking with her own latent powers.
For an additional interpretation consult the entry for Follow / Follower.