[hard] Phonetics: bunched r

[nonnativespeaker]

I can produce retroflex r [ɹ̠ʷ] but not bunched r [ɣ̞ʷˤ] or [ ɹ̈ ] (velar bunched approximant)
I have created this question How to pronounce the "bunched /r/" sound?
It took me 2 years and I still cannot pronounce [ ɹ̈ ].
Any ideas?

 

[5jj]

Why do you want to?

I can produce retroflex r [ɹ̠ʷ] but not bunched r [ɣ̞ʷˤ] or [ ɹ̈ ] (velar bunched approximant)

I would guess that 99% of native speakers would not know what sounds the symbols [ɹ̠ʷ], [ɣ̞ʷˤ] or [ ɹ̈ ] represent.

 

[Tarheel]

Try:

I've been working on it for two years, and I still haven't figured it out.

Well, I don't know what a bunched "r" is.