Shackled by flipping extreme dominatrix's device (5)
I believe the answer is:
modem
'device' is the definition.
(I have seen 'electronic device' mean 'modem' so perhaps 'device' could also mean 'modem')
'shackled by flipping extreme dominatrix's' is the wordplay.
'MODEM' is hidden back-to-front within the letters.
But, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for modem that I've seen before include "Device linking computers via a telephone line" , "Phone-to-computer connector" , "Device used with computer" , "Telephonic computer connection" , "Device for connecting two computers" .)