I think the humour should be the key.
And also ,serve him the same thing.When he is PF,if YOU let him fly give him the same amount of callouts.
Maybe he'll be smart enaugh to realise his mistake,otherwise you can point it out at the end of the flight.
Also,you can demonstrate to him his lack of awareness by asking some questions :for ex if he continues to tell you to "watch your airspeed" ask him what's the wind,the VSI,the DME,actual weight,the next freq,eng vibration,etc.....
Also you can brief the calls you want to hear and when if you see he's going out of the book.
And if you see he's doing all that on purpose,just to annoy you ,don't forget,you're the cpt, a.k.a the BOSS.
Brgds....
Alex