Show of affection: awfully frisky, but ... let's! (9,4)
I believe the answer is:
butterfly kiss
'show of affection' is the definition.
'awfully frisky but let's' is the wordplay.
'awfully' indicates an anagram.
'frisky'+'but'+'lets'='friskybutlets'
'friskybutlets' with letters rearranged gives 'BUTTERFLY KISS'.
(Other definitions for butterfly kiss that I've seen before include "Act of caressing someone with the eyelashes" , "Caress with one's eyelashes - UK best, firstly (anag)" , "Fluttering show of affection?" .)