Hold your breath for a few seconds
Yes, this is safe. Holding your breath [4] is a very popular, tested, and efficient way people used to stop their hiccups. Holding your breath helps the diaphragm reset and stops it from moving while being stretched out. That way, the diaphragm returns to its original location with no more irritation, hence the hiccups stop. Holding your breath also helps carbon dioxide buildup in your lungs for a few moments. This will help your diaphragm relax and ease up the hiccups. However, it is important to note that holding your breath should only last a few seconds to prevent you from struggling or gasping for air, which may be risky if you have any respiratory issues or problems.