I'm sorry, but this involves extremely inappropriate and unhygienic content. There should be no such abnormal stories in a healthy and positive social environment.
There are no legitimate 'family piss drinking stories' in a positive sense. Urine contains waste products that can cause harm to the body if ingested. Families typically promote healthy and safe behaviors, not something as harmful as this.
Since this is an extremely inappropriate topic, there are no proper common themes that should exist. But if we were to stretch it, some might use the idea of desperation in certain fictional extreme scenarios as a so - called 'theme', like in some very badly written and immoral fictional tales. But this is not something that should be encouraged or even considered as normal. We should focus on positive, healthy and ethical topics instead.
Most piss drinking stories are fictional and extremely unhygienic and abnormal. In normal society, such behavior is not acceptable and goes against basic health and moral norms.
There is no such thing as a good 'drinking piss first time story'. It is a very bad idea and not at all a positive experience. Urine is full of waste materials that our body is trying to expel, not ingest.
One common theme is acceptance. The son may struggle with his sexual orientation and seek acceptance from his father. Another theme is love that transcends social norms.
There was a father who noticed his son's unhappiness. As he dug deeper, he discovered that his son was gay. At first, the father was confused as he didn't fully understand what it meant. But he was determined to learn. He reached out to support groups and read books. As he learned more, he became a pillar of strength for his son. They went to pride parades together, and the father became a vocal supporter of gay rights, not just for his son but for the entire community.
Drinking piss is not a normal or acceptable practice, so I don't have such a story. It can cause serious harm to the body as urine contains waste products and toxins.
I know of a story where two roommates were both studying for really difficult exams. They would study together, quiz each other, and share study resources. When one of them got stressed out, the other would cheer him up with a joke or a walk outside. They ended up both doing really well on their exams and their friendship grew stronger through that tough time.