Centrally heated room mostly being used for procreation (2,4)
I believe the answer is:
at stud
'centrally heated room mostly' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'being used for procreation' is the wordplay.
I cannot really see how this works, but
'being' could be 'stud' (stud is a kind of being) and 'stud' is found in the answer.
The remaining letters 'at' 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).
Can you help me to learn more?
(Another definition for at stud that I've seen is " Being used for breeding purposes".)