Was the joke directed at you? Or was it just a stuttering joke? Personally I am always a little bit miffed when I hear the "did I stutter?" phrase. But I also recognize that it's not being directed at me. I often comment that I hate that expression after being a stutterer for years. It sounds like no one had ill intent. You could respond with a meme of your own. https://imgflip.com/i/6acowm