Is successful (in establishing a friendly relationship?) (4,2)

I believe the answer is:

gets on

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'is' is the definition.
The definition and answer can be both to do with social activities as well as being verbs in their -s form.
Maybe they are linked in a way I don't understand?

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for gets on that I've seen is " Makes progress".)

I've seen this clue in the Evening Standard.

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