How do you stop an asthma attack when your rescue inhaler is not working?

You didn't mention where you are when this occurs. In the middle of woods, in Times Square? But ok, you're going to be anxious and maybe panicky. Try to pant, breathe on top of your lungs fast. No you don't have to stick your tongue out. There is nothing you're going to do but try to stay calm until help arrives. Pant and say to yourself "I'm not going to let this get me.". Repeat until you get to a hospital. And keep trying your inhaler. Eventually it will work.
Always have your inhaler with you no matter what. If you're going swimming tuck it into your bathing suit, it's waterproof. I don't care what situation you're in keep it close by. If that limits your social life I'm sorry but It's better than the alternative.
God bless.
Oh yeah, if someone tells you to "breathe in through your nose and out through your mouth" tell them to run around the block and then try breathing that way. Believe me I've been there and that's exactly what I couldn't do.If I could do that I wouldn't be having trouble! I know people are well intended but they just don't really know what it feels like.

First and foremost stay calm and don't panic. get a paper towel that has warm water on it put a few small holes in it and try your best to breathe through it. I had sport induced asthma and when my inhaler didn't work that is what i used it normally helped cause it gets your normal breathing pattern back on track and oddly calms the nerves.

Caffeine helps. If you have access to coffee, or a really high caffeinated drink (energy drinks!) then drink up. Stick your head in a freezer. The dryness helps bunches, but then again, the cold can make it worse.

If you can, any anti-inflamatory medicine, such as an epipen would be useful. Try to call for an ambulance if you have a phone handy.

stay calm and go to the nearest emergency room for a breathing treatment and steroids