I get it but why is it embarrassing to write if you were clearly blocking and the dude just wanted to help? If you're not ashamed of the stutter you should stfu, look him in the eyes, take the paper and write. The humiliation is in your mind bcs he had no intention of humiliating you, he only wanted to help so accept the help. Am not going to tell you the "you will get over it" and motivational video bs. This is gold advice bcs i have been there.