Ready for some sex? (2,2,2)

I believe the answer is:

up to it

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'ready' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'some sex?' is the wordplay.
'some' becomes 'upto' (I can't justify this - if you can you should give a lot more credence to this answer).
'sex?' becomes 'it' (a common euphemism).
'upto'+'it'='UP TO IT'

'for' is the link.

Can you help me to learn more?

I've seen this clue in The Hindu.

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