Bet your eyelashes can do this! (7)
I believe the answer is:
flutter
This clue is a double definition.
'bet' is the first definition.
(I have seen 'Small bet' mean 'flutter' so perhaps 'bet' could also mean 'flutter')
'your eyelashes can do this' is the second definition.
(as in fluttering one's eyelashes)
(Other definitions for flutter that I've seen before include "Fly unsteadily; small bet" , "Move one's eyelashes - move like a butterfly - bet" , "Bat" , "Informally a slight gamble as on a horse" , "Small bet; beat feebly" .)