A little drink from a siphon (3)

I believe the answer is:

sip

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

'a little drink' is the definition.
(I've seen this in another clue)

I don't understand the remainder of the clue.

(Other definitions for sip that I've seen before include "Drink in tiny mouthfuls" , "Take in slowly" , "Take small mouthfuls of (drink)" , "Drink slowly" , "Small mouthful of fluid" .)

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.