Tongue

Hello :) 

I would like to ask about where the tongue should be placed when singing long notes and in general? :)

Thank you

In general (low notes included), it should be relaxed with the front of the tongue resting behind your bottom teeth. Your tongue needs to be flexible and ready to move (for consonant articulation), so it's more important that it's relaxed than that it's holding one position at all times. Some teachers (more classical teachers) believe that the NG shape (with an arch in the tongue) is ideal. I do like the NG position, but I don't usually teach it as the "gold standard" for tongue placement. If your tongue feels like it's tensing, getting "stuck" in one position, retracting, or pressing down in a flat position, then singing on an NG could be very helpful (and then opening from NG to a vowel by lifting your soft palate). You can also use syllables that necessitate tongue movement, ie: A-E-I-O-U (tongue shaping the vowels rather than the jaw), or singing on a syllable like DOO or LOH so the tongue is active. 

Alrighty, Thank you camille :)

No problem, Kerrie!