We can avoid such topics by setting a good moral standard for ourselves. When a conversation starts to head in that direction, simply change the subject to something more positive, such as travel experiences. Also, encourage others to also stay away from such vulgar topics through our own good example.
To avoid this kind of topic, we need to have a strong sense of propriety. In social situations, we can initiate conversations about current events, cultural events or achievements in various fields. Moreover, if someone else tries to bring up such a topic, we can politely but firmly indicate that we don't want to discuss it and redirect the conversation to a more appropriate area.