"Sum and substance" refers to the essential meaning or the most important aspects of a topic or discussion.

"To fool around" generally means to spend time in a lighthearted or playful manner, often without any serious intent.

The phrase "draw a blank" is an idiomatic expression that means to be unable to remember something or to fail to come up with an answer. It often occurs in situations where someone is trying to recall information but can't think of it at that moment. For example, a student might "draw a blank" during an exam when faced with a question they can’t answer.

The phrase "by the rule of thumb" refers to making decisions or judgments based on practical experience or general guidelines rather than precise measurements or strict rules. It implies a level of flexibility and reliance on intuition.

The phrase "to blaze a trail" means to be a pioneer or to lead the way in a particular field or area. It often refers to making significant advancements or innovations that others may follow, indicating courage and initiative.

The phrase "a snake in the grass" describes someone who is deceitful or treacherous, often hiding their true intentions. It implies that the person may seem innocuous or trustworthy but has a hidden agenda that poses a threat.

The phrase "to take a leap in the dark" refers to taking a risk or making a decision without knowing the outcome, often involving uncertainty or a lack of information. It conveys a sense of courage or recklessness in venturing into the unknown.

The phrase "face the music" means to confront the reality of a situation, especially the unpleasant consequences of one's actions or decisions. It implies accepting responsibility and dealing with any fallout that results from those choices, rather than avoiding or denying them.

The phrase "soft soap" refers to the act of using insincere flattery or smooth talk to persuade or manipulate someone. It implies an element of deception, where the speaker may not genuinely mean what they are saying but uses charm or compliments to achieve their goals. The term suggests a slick, slippery manner of communication, akin to using a soft, slippery soap to make something easier to handle or manipulate.

The phrase "on cloud nine" is an idiomatic expression that means to be in a state of great happiness or euphoria. It suggests a feeling of being blissfully happy, often as a result of good news or a positive experience. The imagery of being high up in the clouds conveys a sense of lightness and joy, reflecting a peak emotional state.