talk someone's arm off
Also, talk someone's ear or head or pants off; talk a blue streak; talk until one is blue in the face; talk the bark off a tree or the hind leg off a donkey or horse. Talk so much as to exhaust the listener, as in Whenever I run into her she talks my arm off, or Louise was so excited that she talked a blue streak, or You can talk the bark off a tree but you still won't convince me. The first four expressions imply that one is so bored by a person's loquacity that one's arm (or ear or head or pants) fall off; they date from the first half of the 1900s (also see pants off). The term like a blue streak alone simply means "very quickly," but in this idiom, first recorded in 1914, it means "continuously." The obvious hyperboles implying talk that takes the bark off a tree, first recorded in 1831, or the hind leg off a horse, from 1808, are heard less often today. Also see under blue in the face.