"Something shiny" here may be referring to money, and to how, in the past, the Church demanded the people to give it money, called 'indulgences'. These 'indulgences' were said to be paid so that the person who gave them would be have their sins forgiven by God, ie. they had to pay to 'keep the Goddess on my side'. Here, Hozier makes the point that money is not the main currency anymore; flesh - 'meat' - is. Therefore, he is paying the Goddess with sacrifices.