A man who was a hump-back once met the fairies dancing, and danced with their queen; and he sang with them, "Monday, Tuesday, Wednesday," so well that they took off his hump, and he returned home a straight-bodied man. Then a tailor went past the same place, and was also admitted by the fairies to their dance. He caught the fairy queen by the waist, and she resented his familiarity. And in singing he added "Thursday" to their song and spoilt it. To pay the tailor for his rudeness and ill manners, the dancers took up the hump they had just removed from the first man and clapped it on his back, and the conceited fellow went home a hump-back.
Source: W. Y. Evans-Wentz, The Fairy Faith in Celtic Countries (London and New York: H. Frowde, 1911), p. 92. Evans-Wentz's source for this tale was a protestant minister who had lived in the West Hebrides. This story comes from Benbecula in the Western Hebrides.