Exercise in burning logs here perhaps (4,4)
I believe the answer is:
open fire
'logs here perhaps' is the definition.
The definition suggests a singular noun but the answer is not.
'exercise in burning' is the wordplay.
'exercise' becomes 'pe' (Physical Education).
'in' is an insertion indicator.
'burning' becomes 'onfire' (I've seen this before**).
'pe' placed into 'onfire' is 'OPEN-FIRE'.
Can you help me to learn more?
(Other definitions for open fire that I've seen before include "Perhaps start sniping" , "Begin to shoot" , "where things may be hotting up" , "domestic hot spot" , "This may need log on to start" .)