Sinks begin bubbling over, gushing and seething (4)

I believe the answer is:

bogs

I'm a little stuck... Click here to teach me more about this clue!

'sinks' is the definition.
The definition and answer can be both related to change as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?

'begin bubbling over gushing and seething' is the wordplay.
'begin' says to take the initial letters.
'and' is a charade indicator (letters next to each other).
'seething' becomes 's' (this could be a standard abbreviation of which I'm unaware).
The first letters of 'bubbling over gushing' is 'bog'.
'bog'+'s'='BOGS'

Can you help me to learn more?

(Other definitions for bogs that I've seen before include "Swamps or marshes" , "Wet spongy areas with decomposing vegetation" .)

I've seen this clue in the Sydney Morning Herald.

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