I use Android Studio on Mac, all on the latest version. Say I'm doing this:
SQLiteDatabase db;
db = yourAppContext.openOrCreateDatabase("db.sqlite3", Context.MODE_PRIVATE, null);
Thanks to this link:
http://www.c-sharpcorner.com/UploadFile/e14021/know-where-database-is-stored-in-android-studio/
you can precisely find the directory containing your actual SQLite3 database on the emulator while it is running:

Quality goods.
Next, you can click the Pull button and pull this file to say your desktop on Mac. Awesome.
But how do you actually literally find this folder (in this example, the "database") on your Mac?
that is, using a regular shell terminal, I want the "CD" to go there.
, nix Mac?