If you're boiling in a pot and a stirrer (spoon, ladle, etc.) doesn't appear, it most likely means you need to blow. But, if you're in a noisy place with lots of surrounding air, you can lose marks because "you blew at the wrong time". So just a suggestion: Try not to do a recipe, such as the T-Bone Steak, when you're in an area with lots of surrounding air.

Some rooms that may have surrounding air are:
The car with the window open/noisy people talking/air conditioner on, a restaurant, outside