The idiom "under siege" means to be surrounded or under attack, especially by a group of people or entities that are hostile or oppressive. It can also mean to be in a difficult or dangerous situation, where one feels besieged or overwhelmed.

The idiom "dos and don'ts" is a set of rules or guidelines for what is acceptable and not acceptable behavior in a particular situation or context. It can also refer to a list of instructions or tips for how to do something correctly.

The idiom "a wet blanket" refers to a person who is overly negative, critical or unenthusiastic about something. They are often the ones who bring down the mood of others by dampening their spirits with their dampened attitude and lack of enthusiasm.

The idiom "ring fencing" means to create a physical or psychological barrier around something or someone, to protect it from external threats or influences.

The idiom "you're on" means that someone is about to start doing something, or that they have already started but are not yet ready to tell anyone else about it. It can also be used as a way of encouraging someone to do something or to congratulate them on starting something new.