David's Tip of the Day: Tongue Position - Part 3 (Tuning your Mouth)
As your bending skills develop on the harmonica, your tongue and jaw learn how to dynamically tune your mouth to the pitch of each reed you're playing. When playing the 2 draw your jaw is slightly dropped and your tongue is lowered slightly in the back... for the 4 draw your jaw doesn't drop and your tongue is slightly (emphasis on "slightly") humped in the middle... and for the 6 draw your tongue is slightly forward in the mouth... all of this allowing a bend to happen the moment the tongue moves upward to start the bending process... this is what allows players to play faster as their bending skills develop (bend responds faster).
So, to sum up from the past couple of tips...
To FIX issues of unwanted bending, squealing and stalling of notes, dropping your tongue in the back (tuning your mouth very low) is usually the answer. You can also raise the entire length of the tongue (tuning your mouth very high), but at the detriment of tone (thin/whiny). The eventual position of the tongue is that of tuning your mouth to the pitch of the reed you're playing, and is something that happens over time with experience (good tone with added advantage of bends that respond immediately).