Instead of trying to force yourself to do the thing, refuse to do anything else. Instead of replacing activity with another, just sit still either eyes closed or looking at a wall or desk (not a screen or anything entertaining). Only replacement activity should be no activity, pure boredom. Don't judge yourself and don't feel quilt. If you are stubborn with this, you may notice that you start doing the thing as an impulse without seeing the decision to act coming. Somehow the motivation is there but your constant emotional monitoring is blocking it.

If you start to procrastinate with the procrastination avoidance, all hope is lost.