Getting ready to drop litter? (2,3)
I believe the answer is:
Here is my best explanation:
'getting ready to drop' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'litter?' is the subsidiary indication.
I cannot quite understand how this works, but
'litter?' could be 'pup' (pupping is a kind of littering) and 'pup' is present in the answer.
The remaining letters 'in' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).