If you block when you're by yourself I think it's an amazing opportunity to practice moving to the sound you're afraid to vocalize. For most people this is a vowel sound since those are open sounds and sound the weirdest if you openly stutter on them. I would also remind yourself to not push and take all the time you need. You don't want to push through tension but stay in that block and play around with hoe you can reduce the tension and then doing what you need to do with your mouth and throat to produce the blocked sound.