Double Flam Drag
The Double Flam Drag is just a standard Flam Drag with an additional drag. In this case it’s basically a group of 5 with added partials on the 1st, 2nd, and 4th notes.
Step 1: Playing the skeleton of this hybrid rudiment would just be fivelets with an accent on the first note.
Step 2: Add a grace note to the accent to make it a flam then place the diddles on the 2nd, and 4th note of the fivelet and that completes the hybrid rudiment making it a double flam drag.
A simple analogy to think of hybrid rudiments would be to imagine a Christmas tree. It’s just a pine tree until you add the lights and ornaments.