Bed heaving with lice making a bit of noise (7)
I believe the answer is:
decibel
'a bit of noise' is the definition.
'decibel' can be an answer for 'noise' (I've seen this before). I'm not certain of the 'a bit of' bit.
'bed heaving with lice' is the wordplay.
'heaving with' is an anagram indicator (letters thrown or heaved around).
'bed' mixed up with 'lice' gives 'DECIBEL'.
'making' is the link.
Can you help me to learn more?
(Other definitions for decibel that I've seen before include "Unit of measurement for loudness" , "I relate to volume" , "Unit of volume" , "Sound level unit" , "Measure of sound" .)