As part of a speech therapy program I had to practice street contacts, e.g. stopping someone and asking how to get to some place I found it hard to say. I was becoming more accepting of my stammer at the time and did sometimes chuckle when it reared its ugly head. Some people thought I was laughing at them as if I was playing some prank on them and they got quite annoyed. On the other hand, with understanding friends, it's fine to laugh about it. Laughter is a great way to deal with negative perceptions and beliefs. Even jokes about suicide helped me through times of suicidality. Be mindful of the context in which you are using humour and it can help.