How to "dirty talk"?

My SO is super into dirty talk and I just have no idea on where to even start. 
Even when we very first started dating he would mention it and try and encourage me to do it. 
At first I was just really embarrassed about the whole thing but now it's more like I think I'm gonna say something stupid and completely ruin the mood. I'm scared that my voice doesn't sound sexy at all. Lol
Any of you girls have any advice? 
Any keywords your man loves that I can steal and try out on mine? 
Anything helps. 💕