How do I stop sucking my thumb?

Why do it? The real question is, "what does thumb sucking accomplish?" for small children, it's easy. It eases boredom, provides relaxation and some mild stress relief. For adults, it can do a lot of the same things, but most adults have learned other coping skills, or learned to deal with life's stresses. Thumb sucking obviously serves a purpose, and a therapist can help find them and form new coping skills.
Age? If you are old enough to write this as a personal question, its probably a stress reliver & u hate it when you catch yourself.I believe there are some unobtrusive thumb guards out there that you can attach that would immediately remind you whats happening. Dentists can sometimes attach a retainer that prevents u from maintaining suction.Self hypnosis might help if you could find good instruction.