Clear up hot argument with lover primarily in sack tonight (5,5,2)
I believe the answer is:
throw light on
'lover primarily in sack tonight' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'clear up hot argument' is the wordplay.
I cannot quite understand how this works, but
'clear' could be 'light' and 'light' is located in the answer.
'hot' could be 'h' and 'h' is found within the answer.
'argument' could be 'row' (I've seen this before) and 'row' is present in the answer.
The remaining letters 'ton' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'with' is the link.
Can you help me to learn more?
(Another definition for throw light on that I've seen is " Clarify, help to explain".)