Accepting a humiliatingly small tip? (9,2,6)

I believe the answer is:

pocketing an insult

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

'accepting' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'a humiliatingly small tip?' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is present in the answer.
'small' could be 'pocket' (I've seen this before) and 'pocket' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.