First, you should not believe it easily. It could be a baseless rumor. But if there are signs that it might be true, you should report it to the relevant authorities. This is because drug use is illegal and endangers lives.
There might be some fictional or extremely rare and abnormal accounts that could be misconstrued as such 'stories', but they are not something to be glorified. In most cases, these are likely to be part of a very dark and dysfunctional scenario that no one should be involved in. It's important to promote positive family relationships and stay away from drugs.
If you hear such stories, you should distance yourself from the source. You can also let the person know that this is not something that should be talked about as it is disrespectful and unethical.
One should firmly refuse to listen further and ask the person spreading it to stop. It's not something that should be entertained.
Ignore it. Don't participate in spreading such inappropriate information.
First, you should realize that this is not a normal or acceptable situation. You can talk to the person sharing the story, if appropriate, and explain why this is wrong. Encourage them to focus on positive family interactions that are based on respect and healthy boundaries, like going on a picnic or playing family games together instead of this inappropriate scenario.
Just ignore them. These stories are often not based on facts and are just for creating a false image. Focus on the real aspects of Berghain like its music and art scene.
If it was accidental, they should immediately distance themselves and try to forget about it. Pretend it never happened and respect the privacy.
One should immediately stop the person from sharing such inappropriate stories. It's important to set boundaries and make it clear that this kind of talk is unacceptable.
If you hear such stories, the first thing is not to believe them blindly. As mentioned before, these are likely to be untrue or exaggerated.
One should not spread it further. Ignore it if possible. If it's causing discomfort or seems unethical, one could report it to the appropriate authority in a proper way, like the school or sports organization's ethics committee if it's in a sports context.