Thrust forward onto the organ bearing (5)
I believe the answer is:
lunge
'thrust forward' is the definition.
(I've seen this before)
'organ bearing' is the wordplay.
'organ' becomes 'lung' (lung is a kind of organ).
'bearing' becomes 'e' (East, a compass bearing or direction).
'lung'+'e'='LUNGE'
'onto the' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for lunge that I've seen before include "dive" , "Sudden thrust in fencing" , "Thrust forward as with sword" , "Make a thrusting forward movement" , "Stab" .)