A person whether it be male, female, or whatever who will only engage in sexual intercourse or activity when it takes place during an Orgy, usually involving a minimum of 5 distinct persons (animals not included).
Robert: Man, I spent three hours talking up Helen last night and buying her drinks thinking I was going to score, but wouldn't you know it she's an OSexual and wouldn't go back to my place unless there were two more couples going to join us.
Shawn: Shit! I wished you would have called me as I was out with the Mrs. and our neighbors Heather and Bill. They were both loaded up on Pino and cocaine and would have been down for anything...especially cleaning Helen's butthole.
The most irrisitble girl to ever exist. Once you meet an Oseremi, you’ll never want to leave their side. They can be prettyblunt, slow, and snobby sometimes, but once you become close with them, you’ll fall in love. They are so cute and nice, any guy is lucky to have her...
Becky: “Oh my god, Brad left me for an Oseremi..”
Chris: “Makes sense, i’d leave you too for her”