Gentle attention-getter
I believe the answer is:
tap
'gentle attention-getter' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tap that I've seen before include "1dn to get on the phone, perhaps!" , "Intercept; light knock" , "A form of dance" , "Somewhere to drink beer" , "Sort of dance" .)