Stick together a bit of collage, in this case (6)
I believe the answer is:
cohere
'stick together' is the definition.
(to cohere is to stick or fit together)
'a bit of collage in this case' is the wordplay.
'a bit of collage' becomes 'co' (I can't explain this - if you can you should give a lot more credence to this answer).
'in this case' becomes 'here' (I've seen this in another clue).
'co'+'here'='COHERE'
Can you help me to learn more?
(Other definitions for cohere that I've seen before include "Fit together" , "Stick together, remain united" , "Form a whole" , "Hang together" , "Be consistent" .)