This app was mentioned in 2 comments, with an average of 3.50 upvotes
I've heard of this technique, but haven't tried it. I never knew there was an app to talk you through it. Thanks!
For the lazy: this is the app I found: https://play.google.com/store/apps/details?id=autogenicdrainage.polemics.com.autogenicdrainage&hl=en
Yes, I've used this one for Android and it seems to work.
https://play.google.com/store/apps/details?id=autogenicdrainage.polemics.com.autogenicdrainage