Incense first two joiners working on ship, giving them some criticism (9)

'incense first two joiners working' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'on ship giving them some criticism' is the wordplay.
'on' is an insertion indicator (as in clothing 'on' a person).
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'giving' says to put letters next to each other.
'them' becomes 'jo' (I can't explain this - if you can you should give a lot more credence to this answer).
'some criticism' becomes 'stick' (giving someone stick is criticising them).
'jo'+'stick' is 'jostick'.
'ss' put into 'jostick' is 'JOSSSTICK'.

Can you help me to learn more?