Question

How do you stop the opponent from Coaching in Doubles OU?

Comments

You could try Taunt, knocking them out, bribing them to not use the move, or threatening to find out where they live and punish them.

---

Lol Giga

Answer 1

Taunt prevents status moves from being used, and Coaching is a status move. Coaching also fails when there is no target for it to help.
Sources: https://www.smogon.com/dex/ss/moves/taunt/ and https://www.smogon.com/dex/ss/moves/coaching

Comments

Or, you could do what Giga said, but I don't recommend it, as it probably wouldn't work for the first option, and if it did, that would be bad, the second one probably wouldn't work either, and the last would probably get you banned on showdown.

---

Don't be ridiculous. My ideas are so much more effective.
/s

---

I know, your ideas are way better.