Poke fun (at) (4)
(Other definitions for rib that I've seen before include "Bone; supporting member" , "Hinged rod in umbrella" , "Eve is knownj as Adam's . . ." , "Tease; body part" , "One of the 12 pairs of curved arches of bone" .)
'poke fun at' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for kid that I've seen before include "To fool; young animal" , "Joke" , "Pretend" , "Rib" , "A baby goat or informal child" .)
(Other definitions for jape that I've seen before include "Trick or prank" , "Jolly wheeze" , "Trick - joke - jest" , "Lark" , "Jolly joke" .)