1) Yes we 100% know when we're stuttering. In fact most of us know when we start a sentence which word we are going to stutter on. If your friend looks like she's having a seizure, it's because she's struggling with all her might to get a word out, and all her muscles are tensing up which can look like she's having a seizure without actually having one. Non-stutterers don't reslize that talking with a stutter can be physically exhausting if they're blocking on words a lot. 2) I personally hate when people try to finish my sentences, and I find most other stutterers do too. It makes me feel like other people don't think I'm capable of expressing myself without their help, and that feels super infantilizing. Sometimes they also keep guessing the end of the sentence wrong so then I have to stop what I'm trying to say to tell them "no, it's actually...." and then the whole stuttering cycle repeats itself. Finishing their sentences for them is a good way to ensure they stop talking to you period. 3) No I almost never tell people off the bat that I have a stutter. That can be super awkward and also makes the other person identify you as having a disability before they even get to know you. I don't wish to be defined by my stutter. Do you also go around telling people at the beginning of a conversation that you have ADHD or that you have a bad knee? For me, it's the same. The only exception I've made is when I had to do oral exams for med school with patient actors who were grading me. I told them for the sake of being graded fairly that I may stutter but that I wouldn't let that get in the way of my exam.