... exhales from occasionally briefer kiss (5)
I believe the answer is:
reeks
'exhales' is the definition.
The definition and answer can be both related to bodily activities as well as being verbs in their -s form.
Perhaps you can see an association between them that I can't see?
'occasionally briefer kiss' is the wordplay.
'occasionally' means one should take alternating letters.
'briefer'+'kiss'='brieferkiss'
The alternate letters of 'brieferkiss' are 'REEKS'.
'from' acts as a link.
Can you help me to learn more?
(Other definitions for reeks that I've seen before include "offensive odours" , "Macgillycuddy's - -" , "Stinks to high heaven" , "Gives off a strong unpleasant smell" , "Smells like the Kerry mountains." .)