Hi, i have a mild stutter too, i stutter more than 15 times a day though, but most of the time it doesn't affect me that much ( which is why i consider it mild ) but in some case i find myself stuttering more. Just like you, small intimate situation are the best, and large group talk are the worst. When i'm with people i don't know i tend to be more stressed/ tense, which make me stutter more. In those type of situation i have to really focus and speak slower, and apply all the techniques i've been taught to relax my larynx. Most of the time if i focus it does work. But yeah i think all mild stutterers tend to do better in relax situations and worst when they are tense.