Use 'bottle it' in casual or informal situations, not in formal writing or speeches.

Context Sensitive

Remember it's mostly used in the UK, so it might not be understood by English speakers from other regions.

UK Specific

'Bottle it' often implies criticism or disappointment in someone's lack of courage.

Using 'bottle it' suggests that not expressing emotions could be unhealthy.

In some cases, 'bottle it up' reflects a temporary way of dealing with emotions.

'Bottle it up too long' warns that keeping emotions inside for too long is not good.