A play on the early 90's rapper Sir-mix-Alot. Someone enthralled with the sound of their own voice. a person who you avoid conversations with because you know it will be a waste of a half hour of your life. An interchangeable derogatory term for someone who does something too much: sir-smokes-alot, sir-stinks-alot, sir-eats-alot, etc
thank sir-talks-alot, I wish we could sort this out tomorrow, but I don't have a free two-hours, so just send me an email.