Kusuriyubi Hime
From Shoujo Crusade:
The qualification for a princess is for a prince to be beside her. Hinaki, who wishes to become a real princess, is a genuine girl. Around Hinaki there is Yume-senpai, who is almost annoying but is really just trying too hard, and other boy followers, but no one is Hinaki's "prince". The "prince" who should be beside Hinaki is inside her ring...!?