A little dog - perhaps one plays with it (3,7)
I believe the answer is:
Here is my best explanation:
'a little dog' is the definition.
'perhaps one plays with it' is the subsidiary indication.
'perhaps' indicates anagramming the letters.
'with' means one lot of letters go next to another.
'oneplays' after 'it' is 'itoneplays'.
'itoneplays' is an anagram of 'toyspaniel'.