Lucky creature, not large, caressing Henry’s cheek (8)
I believe the answer is:
backchat
'cheek' is the definition.
(both can mean insolence or rudeness)
'lucky creature not large caressing henry's' is the wordplay.
'lucky creature' becomes 'black cat' (black cats are sometimes considered lucky).
'not' indicates named letters should be taken away.
'large' becomes 'L' (eg in clothes sizes).
'caressing' means one lot of letters goes inside another.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'blackcat' with 'l' taken away is 'backcat'.
'backcat' going around 'h' is 'BACKCHAT'.
(Other definitions for backchat that I've seen before include "Impertinence" , "Impudent retort" , "Impertinent remarks" , "cheeky retorts" , "Insolence" .)