Fake stuttering helps me with this. I know it sounds weird, and I have no clue why it helps, but it does. So if you were going to say “tomorrow I’m going to a baseball game” and you know you are going to block on baseball, deliberately stutter at the beginning of the sentence (I guess this is assuming you are fluent in the sentence except for the B word)… for me this really helps to prevent the block in the middle of the sentence. Seriously, if I fake-stutter right at the beginning of a sentence, I’m almost always fluent for the rest of the sentence