What does the cryptic crossword clue "Nip backwards and forwards serving fizzy drink (3)" mean?

The definition is "fizzy drink". The wordplay uses a reversal. reverse of POP = POP; definition: "fizzy drink" The answer is POP.

Nip backwards and forwards serving fizzy drink (3)

Times Cryptic #29168 | 7 Across | 2025-03-04 flower