After coupling with another, tech billionaire stretches (9)
I believe the answer is:
elongates
'stretches' is the definition.
('elongate' can be a synonym of 'stretch')
'after coupling with another tech billionaire' is the wordplay.
I cannot quite understand how this works, but
'another' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
'billionaire' could be 'gates' (I've seen this before) and 'gates' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for elongates that I've seen before include "stretches" , "lengthens the process" , "Extends" , "pulls out" , "tortures on the rack!" .)