When I was young (around 14yo),I was living in Sydney, my best friend and his family took me on their yearly holiday, we went to a country town west of Newcastle.
We were staying at his cousins house, the parents went out shopping one morning left us kids alone, 4 boys and the sister.
We had some chores to do while the parents were out shopping, us boys came to an agreement with the sister, we were all allowed to have sex with her as long as we did the vacuuming and washed the dishes.
This incest was consensual.