It’s called “Voluntary Stuttering” and lets you be in control of how and when you choose to stutter. My daughter does this occasionally. She chooses places where it can be hard (ordering a drink at Starbucks and stuttering on your name) and will do it on purpose. It can take the anxiety away. Sort of like role playing a situation. She sometimes will do it with new friends as well as a way to introduce them to her stuttering or to advertise she is a person who stutters(she is a covert stutterer so it’s not as obvious at first to people) so it signals to them she stutters but she is in control of when and how for this specific situation.