Couples recalling occasionally upbeat dance (3-4)
I believe the answer is:
two-step
'dance' is the definition.
(I know that two-step is a more specific form of the action dance)
'couples recalling occasionally upbeat' is the wordplay.
'couples' becomes 'twos' (I've seen this before).
'recalling' says the letters should be written backwards.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
The alternate letters of 'upbeat' are 'pet'.
'pet' in reverse letter order is 'tep'.
'twos'+'tep'='TWO-STEP'
(Other definitions for two-step that I've seen before include "Sot wept doing ballroom dance" , "Wets opt out of simple ballroom dance" , "Old-time dance in duple time" , "Dance (not pas de deux!)" , "Old time dance" .)