The most common and most likely answer to this crossword clue is the 2 plus 3 plus 2 letter word ON AND ON
I've seen this crossword clue in The Daily Telegraph
O
N
A
N
D
O
N
More clues leading to the result ON AND ON
- . Continually working? A fellow must grab bit of nap!
- Biblical character, fellow apparently lasting forever
- Fellow supporting Judah’s son continuously
- Two legs used in cricket constantly
- Bread eaten by old teacher all the time
- Constantly what makes you get up in the middle of the day dizzy
- … so’s this, as cricket side twice holds country without opener
- Fellow following Judah’s son continuously
- Ever see granny hugged by old teacher?
- Working with a northern fellow never-endingly
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.