I deal with block stutter a lot too. It's so frustrating when I'm listening to a bunch of people talking and I want to say something but I just can't get it out. It's probably the reason why I keep to myself most of the time. Even just one on one is difficult. If I'm asked to repeat something sometimes it comes out fine, but other times I cannot say what I want to. I remember a few days ago I was at Olive Garden, and the waiter asked me what I wanted to drink, and I wanted raspberry lemonade, but could not for the life of me say raspberry. I kept getting stuck on the r sound so I asked for water instead. My dad took notice and after I told him, he ordered the drink for me but it was still an embarrassing moment for me.