Step 1: Unplug the stopper and empty any existing water from the hot water bottle
Step 2: Use your kettle to heat the water. Alternatively, you can run your hot tap water until it reaches its hottest temperature. Do not use boiling water.
Step 3: Hold the hot water bottle by its neck or place in a hot water stand. Fill carefully to a maximum of 2/3 to prevent any water from splashing. If you have a hot water bottle with a cover on it, pull the cover away from the opening before spilling.
Step 4: Gently squeeze the bottle until water appears at the neck then insert the stopper and tighten. Hold the bottle upside down to ensure that it is sealed properly. If your hot water bottle does not have a cover you may wrap it in a fresh, dry towel before using.