digress

digress (http://definr.com/digress)

     v 1: lose clarity or turn aside esp. from the main subject of
          attention or course of argument in writing, thinking, or
          speaking; "She always digresses when telling a story";
          "her mind wanders"; "Don't digress when you give a
          lecture" [syn: stray, divagate, wander]
     2: wander from a direct or straight course [syn: stray, sidetrack,
         depart, straggle]