How do I discourage my cat from playing rough?

[whyameyehere]

We have an about 19 week old kitten that we adopted after finding as an abandoned 12wk old feral. He's a generally lovely affectionate cat but when playing or stroking he will suddenly start playing rough with teeth and claws, I know it's only play but it can still hurts, what's the best way to discourage this?

To stop playing and interacting immediately.

Posted too soon. Then let him calm down, and then go back to playing again. Repeat the stopping playing/interacting as soon as he starts being too rough.

Our feral found in the wild kitten is now seven years old. She will still suddenly bit or scratch us so we then ignore her.