Zecchou-jima no Hime

High school girl Yui is kidnapped and brought to an island along with eight guys (all now criminals) who came from the same orphanage as her. She is strapped with a collar that is set to administer an aphrodisiac to her twice every day, and the guys have to make her come. She has to choose one of them to leave the island with her in one month's time.

(Source: MU, edited)