Get down from there and stop pulling my leg (4,3,2)
I believe the answer is:
come off it
This clue is a double definition.
'get down from there' is the first definition.
(I've seen this before)
'stop pulling my leg' is the second definition.
(both can be used in response to an unlikely claim)
'and' acts as a link.
(Other definitions for come off it that I've seen before include "stop behaving like that!" , "get down from there" , "Drug addict should" , "You're mad!" , "that's most unlikely" .)