Opportunity grasped by heartless lad in evening up for social whirl? (8,7)

'social whirl?' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?

'opportunity grasped by heartless lad in evening up' is the wordplay.
I cannot really see how this works, but
'opportunity' could be 'room' (room is a kind of opportunity) and 'room' is located in the answer.
an anagram of 'lad' is 'lda' which is located in the remaining letters.
'in' is found in the answer.
This explanation may well be incorrect...

'for' is the link.

Can you help me to learn more?