http://www.mangareader.net/datenshi-...-debipara/1/18
http://www.mangareader.net/datenshi-...-debipara/1/19
A New manga that just came out and there is breast expansion in the first chapter. School gets transfered to some kind of Demon world aftert he headmaster completes a magic circle, and one of the main characters ends up asking a demon for large breasts and gets her wish.
Though on the next page seems she wasnt the only girl affected by it