Remaining calm when they imply amusing oneself with tech company is old, in short (7,2,4)
I believe the answer is:
playing it cool
'remaining calm when they imply' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'amusing oneself with tech company is old in short' is the wordplay.
'amusing oneself' becomes 'playing' ('play' can be a synonym of 'amuse oneself').
'with' is a charade indicator (letters next to each other).
'tech company' becomes 'itco' (I can't explain this - if you can you should give a lot more credence to this answer).
'in short' means to remove the last letter.
'old' with its final letter removed is 'ol'.
'playing'+'itco'+'ol'='PLAYING IT COOL'
Can you help me to learn more?