Reminding both sides to drop out of sport in winter (5)
I believe the answer is:
cuing
'reminding' is the definition.
('cue' can be a synonym of 'remind')
'both sides to drop out of sport in winter' is the wordplay.
I cannot quite understand how this works, but
'in' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for cuing that I've seen before include "Acting as a reminder" , "Giving signal to actor" , "manipulating a shock" .)