The Aiora or swinging ritual was first introduced at Athens during the Anthesteria – the hours in between the Choes and Chitron. After a request from a reader and friend I find and translate (my free translation from the Latin text) what I consider to be a nicely presented myth of Ikarios and Erigones. Nilsson in his eminent work the Greek Popular Religion (p.33) considers that is a fertility charm - he discusses more in “Die Anthesterien and die Aiora”, Eranos, XV (1916), 187 ff. The translated text is from the Servius' Commentarius in Vergilii Georgica [ed. G. Thilo and H. Hagen, 2 vols. (Leipzig, 18814)].
For the festivity known as oscilla (the Greek Aiora, Αιώρα) there are different opinions for its origin. Some mention the following myth: the Athenian Ikarios, father of Erigones, when he presented to the mortals the wine which was received from the father Dionysus, was murdered by the farmers, who drank more than was allowed, and they believed that he (Ikarios) had poisoned them. His dog went to his daughter, Erigones, who followed the dog’s trails, found her fathers body and she hanged herself. She, according to Gods’ decision, was transferred to the stars and is the one (constellation) that we call Parthenos. And his dog is the (constellation) Keon. After a short period of time a disease/mania was upon the Athenians that affected all their young women; leaded them to hang themselves. The oracle’s response was that if the disease was to be ended the Erigones and Ikario’s bodies must be found. Regardless their endeavors to find the bodies they were unable to recover them, in addition, to present their respect they draped men by the trees so that it will look like as to search the bodies also in the air. But because few of them were fallen, they thought to create representations of their images for replacements. (ii 389)