It's hard to communicate with your partner, especially if they think they are senior player, without any couching. Teach them how to play might hurt their feeling. It happen to me all the time as I play with different partner each week.

Best thing to do just aim your smash to wherever he/she is standing. If the return straight forward to him, then it would be good.

If you are going for a tourney, find a partner who understand this basic attacking formation.