Talk a blue streak

From Fresh Dictionary

English

Verb

talk a blue streak

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) To talk for a long time, at great length, or to the point of tedium

   She's normally a quiet person, but she will talk a blue streak about fashion, if you let her.