Tail to the right: happy dog! Tail to the left: unsure or worried dog. Tail at half mast, wagging slowly: neutral emotions, calm dog. A wide sweeping wag: friendly greeting. A tentative wag: cautious, “I don’t know you yet.” Straight out, horizontal tail: curiosity. Tail raised high, and erect or waging quickly: releases more pheromones from anal glands, dog on alert, being assertive, may feel threatened. Tucked tail: covers anal glands, indicating submission and stealth.