Pop'n Music M (ポップンミュージックM,Poppun Myuujikku M?) is a mobile game created by KONAMI Net DX, released on January 18, 2011. This app is only required in Japanese FOMA A series or above, additional with a memory card more than 10M. Despite of its release, there is not enough information, and its website is no longer present.
We can only find information about the full game of Pop'n Music M at a Japanese video game website called Inside. 
Not counting promotional in-game screenshots, speaking of the real gameplay, we can only see a screenshot of the results screen with the playable character Kenji, taken by a Photozou user _mopp.
A crossover song from Tokimeki Memorial Girls Side, SHINE by PRIMROSE, made an appearance on Pop'n Music M; albeit, no actual gameplay and game-cut audio were presented. Since pop'n music 20 fantasia's release, SHINE has never been in any arcade-release Pop'n Music title.