I'm working on my slapping and popping. I can slap basic lines, but need improvement. One thing I've been working on is double popping/muting. It's seriously kicking my ass, but here's what I'm doing currently: I set the metronome to triplets, and slap-pop-pop up the E string then back down the A. It ends up being sort of a E minor pentatonic shape. Now, I know progress will be slow, so I'm taking it steady. 10-15 mins of that a day, every morning, plus randomly messing around throughout the day. However, I'm wondering if anyone has any suggestions on basslines to learn to incorperate this as well as any tips on general technique.