I definitely do this. I'll stop in the middle of a word and look around, pretending I'm thinking till I can get the word out. Or I'll just change the word entirely, which doesn't always help. I do this mostly to avoid people knowing, since my stutter only started a few weeks ago and I'm hoping that, as most things do for me, it'll go away before anyone notices. Somehow neither my mom or dad have noticed, only my boyfriend (though I openly talk to him about it) and my little sister (who makes fun of me constantly over it) are aware because I suppose I'm "good" at hiding it, being Covert, as you put it. Though last weekend I was playing Uno with my family, and I had a wild and a hand full of reds, and I put the wild down but couldn't say "red"... So I changed it to green and had to pick up the next turn, much to my dad's confusion. I just shrugged when he asked me why I did it