The two most important elements for tail wagging are:
1. Speed – states the level of excitement. Fast wagging is a sign of excitement or tenseness
2. Radius or the size of the swing – states the emotional condition of the dog
Basic types of tail wagging are:
1. Wide wag is a friendly signal.
2. Strong, wide wag with whole rear end signifies great joy.
3. Light wag with lowered or mid-lowered tail, with small radius, when every swing is small (short) is usually occurring when greeting a dog with no intension to dominate, but innocent and insecure approach.
4. Wag of the high raised tip of the tail in a putteringly manner signifies: curiosity, cautiousness, approach to an unfamiliar dog showing that there is no desire to submit. If the movements are slow and stiff with other signals of communication, whether sound or eye, ear, mouth signals, body posture... it can mean readiness to attack.