The Inuit word aku means 'back flap of woman's parka' (Arctic Sky). I wonder if that is a coincidence or not. Those poor fellows with big smiles on their faces, when they swallowed something (akuaku in Rapanui) it just went right through them.

The back flap of a parka is similar to the rear coat-flap. Although the back flap of the parka has a bottom and things do not fall right through, there is the story about Ulluriaq, a woman shaman, invoking magical power from the stars to ensure her grandson's safe return. He had been caught by the outgoing tide and carried to sea on the moving ice:

Towards late afternoon when there was still some daylight {Ulluriaq} came outside ... apparently to perform an incantation - not a proper shamanistic incantation but one {called} 'quunasiuttuq'. Her hood was tied in the middle, and her aku was also tied by the mid section.

She went to the porch of the igloo and, after a few attempts, managed to climb on to the roof of the porch. Once up, she stood there and cried out a number of times, gesturing with her right arm as if motioning someone to come forward. This is what she said:

Ho, ho! ullirijaat ilaattaa! quunasiutinginniik aturpungaa! Jaru! Jaru! Jaruu! (Ho, ho! with one of the stars, with its power of quunaq I use! Jaru! Jaru! Jaruu!)

(Arctic Sky)

I guess the tying together in the middle was to insure that things would not fall right through, i.e. that her grandson would not become a smiling poor fellow without entrails.