It's a bad problem to have and I used to have it. One thing working in your favor is you know exactly what word you need to say, so you can work on it. Use speech therapy tools like gentle onsets to try to elongate the first sound of the word until you can ease into it. There are other methods too. It's not going to be perfect, but keep working on it. Also, do not ever give a fake name. That is not an acceptable method of word substitution.