Small boy in audition goes over lines randomly (12)

I believe the answer is:

crisscrosses

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

'small boy in audition' is the definition.
I can't judge whether this defines the answer.

'goes over lines randomly' is the wordplay.
'goes over' becomes 'crosses' (I've seen this before).
'lines' indicates putting letters inside (line could historically mean to cover something).
'randomly' becomes 'isscr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'crosses' going around 'isscr' is 'CRISSCROSSES'.

Can you help me to learn more?

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app