There should not be such inappropriate stories in proper literature. Most literature focuses on positive values, moral lessons, and healthy relationships. Such a disturbing concept goes against basic ethical and moral norms, so it is not likely to be a common theme in mainstream literature.
There is no evidence to suggest that such activities occur in a gym environment. Gyms have rules and ethics in place to maintain a proper and respectful atmosphere for all members. This kind of description violates the basic norms of a public fitness place.
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.
Most literature aims to promote positive social values, and topics like this are not part of the acceptable content in literary works. We should look for stories that are about love, friendship, and moral growth in literature.
I'm not aware of any such stories in mainstream popular culture. Truckers are usually associated with their driving jobs, long hauls, and the trucking industry in general, not such inappropriate or vulgar content.