Triple jumping — go for it! (3,3)
I believe the answer is:
let rip
'go for it' is the definition.
'triple jumping' is the wordplay.
'jumping' indicates an anagram.
'triple' anagrammed gives 'LET RIP'.
(Other definitions for let rip that I've seen before include "Act unrestrainedly" , "Speak without restraint" , "Behave without restraint" , "Act violently" , "Release pent-up feelings" .)