Flim and Flam are the best of brothers (and lovers) that compliment each other. While walking one day, a question pops up: "Who's got the bigger dick?" Luna and Celestia make a brief appearance.
Created for the April 2019 Sibling Incest contest by DarkRyu. https://www.fimfiction.net/blog/852094/april-2019-sibling-incest-contest-guaranteed-25-per-submission-300-grand-prize-3000-worth-of-rewards-prizes
RockstarRaccoon pointed this contest out to me. https://www.fimfiction.net/user/126727/RockstarRaccoon