From the manga 'Kuragehime' (Princess Jellyfish) by Akiko Higashimura (Vol. 9 Chapter 49.5/Bonus). If you want to read the whole chapter (english scanlated), it’s available for download over @ Hachimitsu Scans. :)
Note: If you’re not familiar with manga, they’re traditionally read from top to bottom and right to left.
Chansung appeared in Kuragehime (Princess Jellyfish), a manga by Akiko Higashimura.