Why does my 'ta' sound like a 'da' to native speakers? Dealing with retroflex sounds.

I’m a pronunciation-focused learner who records my own voice daily to practice. I’m really struggling with the distinction between the dental and retroflex letters (like ತ vs ಟ). My Kannada teacher tells me I’m 'swallowing' the sound, but no matter how many recordings I listen to, I can't seem to produce the retroflex snap. Does anyone have a specific tongue-placement trick, or should I just try to mimic the audio on Chickytutor.com until it clicks?