The woman's satisfied if coming first, being completely tight (8)
I believe the answer is:
hermetic
'completely tight' is the definition.
(as in hermetically sealing something)
'the woman's satisfied if coming first' is the wordplay.
'the woman's' becomes 'her' (belonging to a woman).
'satisfied' becomes 'met' (as in 'met the conditions of his contract').
'first' indicates taking the first letters.
The initial letters of 'if coming' is 'ic'.
'her'+'met'+'ic'='HERMETIC'
'being' is the link.
(Other definitions for hermetic that I've seen before include "Completely sealed" , "Sealed so as to be airtight" .)