As you know in American English if the "d" or "t" is between two vowels in a word or if it is at the end of a word after a vowel and before a word that starts with a vowel, it is pronounced as a flap sound.(Like in "better", "utter" "I cried on his shoulders" etc.) But also in some cases "d" can be pronounced as a flap sound if it is the fist letter of a word too when it's between two vowels. So, I wonder if I can pronounce the first "d" of "didn't" as a flap sound when it comes after a vowel like in "Why didn't she come with us?", "She didn't like me" etc. I know that the second "d" of "didn't" should be pronounced as flap sound but can I also pronounce the first "d" as a flap sound since it's between two vowels and it is not the main verb, or do I have to make the strong "d" sound like in "Days are passing by"? I feel like it sounds smoother and more natural if I make a flap sound at the first "d" of "didn't" too in the sentences like the ones I gave as examples.
I forgot that you can make a flap sound when "d" or "t" is between "r" and a vowel too so can I make that "flap d" sound in the sentences like "My father didn't come", "Harry Potter didn't kill Hagrid" etc. too? It doesn't sound bad to me after a vowel, but after the "r" it sounds weird to me.