Use 'smack up' when talking about accidents or unintentional damage.

Accidental context

'Smack up' implies severe or significant damage, not a light scratch or dent.

Severity of damage

'Smack up' carries a connotation of violence or force used in the action.

'Smack up' as a drug reference means using drugs, typically in a harmful way.

Using 'smack up' about drugs implies a destructive habit, not casual or recreational use.

'Smack up' is very colloquial and may not be understood universally, even in English-speaking areas.