Continue having sex with hot steno slyly in an extramarital relationship (1,3,2,3,4)
I believe the answer is:
a bit on the side
'continue' is the definition.
I know nothing about this answer so I can't tell whether this works.
'sex with hot steno slyly in an extramarital relationship' is the wordplay.
I cannot quite understand how this works, but
'sex' could be 'it' (a common euphemism) and 'it' is present in the answer.
'hot' could be 'h' (abbreviation eg on taps) and 'h' is present in the answer.
an anagram of 'steno' is 'ontes' which is present in the left over letters.
'an' could be 'i' (Roman numeral for one) and 'i' is located in the answer.
This may be the basis of clue (or it may be nonsense).
'having' acts as a link.
Can you help me to learn more?
(Other definitions for a bit on the side that I've seen before include "as sauce on a plate?" , "Some information about team" , "Mistress?" , "Extramarital partner" , "that endangers union arrangements?" .)