First, let me say that I believe chattiness is a feminine trait, and quiet stoicism is masculine.

Unfortunately for me, I'm probably legitimately ADHD, and I have trouble keeping quiet. My best evidence is a former college roommate who was on meds for ADHD and let me try some of his occasionally. Not only could I focus to study better, it obliterated my need to vocalize every thought in my head. According to my roommate who was well versed in the subject of ADHD, people with it crave a lot more stimulation, and being overly talkative is a symptom of it.

Unfortunately right now I can't be on meds. Eventually I hope to be, but for right now I can't. Long story.

I try to constantly remind myself to STFU and avoid the urge to be chatty, but I often forget and blurt out. What can I do?