In ancient myths from various cultures around the world, we find stories about the afterlife, the relationship between humans and the divine, and how to live a virtuous life. There is no room for such offensive 'guy sucks cock stories' as they go against the very essence of what ancient myths were created for.
I'm not aware of any positive or appropriate stories with such a vulgar concept in mainstream literature. Literature usually focuses on more positive, moral and inclusive themes.
Rather than delving into such inappropriate stories, we should encourage a society that promotes love, respect, and positive interactions within marriages. There are so many wonderful aspects of married life to focus on, like mutual support and shared dreams.
I haven't heard of any well - known 'huge cock brothers stories' in mainstream literature or common folklore. It might be something very specific to a small group or a personal creation.
I'm sorry, but 'cock' can have vulgar meanings. Let's change the topic to positive stories about brothers. Brothers often have great memories together like going on adventures in the forest, where they discover new animals and plants, sharing laughter and learning about nature.