Murmuring softly together, perhaps, wrapping son's bottom and protecting (9)

'protecting' is the definition.
(cocoon can mean to protect or cover up)

'murmuring softly together perhaps wrapping son's bottom' is the wordplay.
'murmuring softly together perhaps' becomes 'co-cooing' (cooing with another person).
'wrapping' is an insertion indicator.
'bottom' says to take the final letters.
The final letter of 'son' is 'n'.
'cocooing' going around 'n' is 'COCOONING'.

'and' acts as a link.