Have fun pulling a lever back (5)

I believe the answer is:
revel
'have fun pulling' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'a lever back' is the wordplay.
'back' is a reversal indicator.
'lever' reversed gives 'REVEL'.
Can you help me to learn more?
(Other definitions for revel that I've seen before include "Be festive, have a good time" , "Make merry; luxuriate (in)" , "Feast riotously" , "Paint the town red" , "Rejoice" .)
