Much talk of getting asleep (3)

I believe the answer is:
gas
'much talk' is the definition.
'gas' can be an answer for 'talk' (gas can mean to chat). I am not sure about the 'much' bit.
'of getting asleep' is the wordplay.
'of' indicates the answer is hidden within the clue.
'GAS' can be found hidden inside 'getting asleep'.
Can you help me to learn more?
(Other definitions for gas that I've seen before include "Talk idly; fuel" , "Domestic fuel" , "Something exciting" , "Empty talk (colloq.)" , "natural resource" .)
