I can usually feel a block coming before it comes. If you are the same, try replacing the word with a synonym. Some times once I start, just stop and take a breath. Use a comfort tick like cover your mouth with your arm to cough, clear your throat, scratch your nose, (and I shit you not, this works for me) turn your hat backwards (or frontwards), run your hand through your hair, act like you got something on your glasses, etc. Some times, creating a visible distraction can distract you and the other person from your block and give you a second to collect your bearings before continuing.