Touch wood / knock on wood
Meaning: said in order to avoid bad luck, either when you mention good luck that you have had in the past or when you mention hopes you have for the future
Example: The deal will be agreed on Wednesday, knock on wood. It's been fine all week and, touch wood, it'll stay fine for the weekend. We haven't had any problems with the car so far, knock on wood.
Example: The deal will be agreed on Wednesday, knock on wood. It's been fine all week and, touch wood, it'll stay fine for the weekend. We haven't had any problems with the car so far, knock on wood.