Here’s a nice Tanpura drone in a to practice your Hariprasad impression with;). Or the sarabande from the Bach Partita!

An here’s a fantastic video of Hariprasad playing with Zakir Hussain

Here’s an explanation of retroflex consonants such as those found in India(Dravidian) languages

Here’s a chart for places of articulation

Lori Colter

Russian Dudes

Here’s Hariprasad in a minor pentatonic(acdeg)

At around 40:50 the double tonguing starts