You can't experience what we experience every day but it's the closest exercise you can do. I wouldn't get hung up on making sure you're convincing enough. If you can walk up to a stranger or stand in a queue and stutter / block in front of other people, I think it's a worthwhile exercise. The point is experiencing what a stutterer experiences (awkwardness of taking a while to get a word out, embarrassment of sounding strange, listener reactions, etc... ). Your focus shouldn't be on how realistic your stutter is.