"CITRIN" is a doujinshi circle consisting of two members "NEGI" and "Hiro Tamura". The circle was first introduced on 2008 as "CITRIN" their first collaboration together, "Jebanni-P no Inori Boshi". CITRIN introduced themselves as a circle on certain events who also produces PVs "who loves Kagamine Rin". Often CITRIN would publish doujinshis in events such as Comiket or Vocaloid only events such as VOC@M@S. In a matter of PV producing, in collaborations NEGI would often do the video with Hiro Tamura doing the illustrations.