I'm not sure what specific 'grandpa cock stories' you mean. It could be some family - related stories about an old rooster (cock) that grandpa had on the farm. Maybe it was a rooster with unique behaviors like waking everyone up very early every day or being very protective of the hens.
To avoid such inappropriate phrases, one should cultivate good moral and ethical values. Think about whether what you are about to say is acceptable in a general social setting. Also, surround yourself with positive language environments, like positive - minded friends and positive media content.
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.
Maybe there are stories where grandpa's rooster had a special talent, like being able to find hidden treats better than any other animal on the farm. This could have led to some fun and interesting tales that grandpa would tell the grandchildren.