Assume being tickled tickles (6)
I believe the answer is:
amuses
'tickles' is the definition.
(tickle can mean to entertain or amuse)
'assume being tickled' is the wordplay.
'being tickled' indicates an anagram (letters tickled out of place).
'assume' anagrammed gives 'AMUSES'.
(Other definitions for amuses that I've seen before include "Entertains" , "Makes (someone) laugh" , "Diverts" , "provides entertainment" .)