to be kind of in a relationship with a guy/girl, but not fully committed any MAYBE not exclusive/monogomous. baically you like eachother and are sexually active, but dont call eachother girlfriend and boyfriend
people who hate committment should be on it-eg teenag boys
girl:i saw you kissing with adam before, are you going out now?
girl2: nah, we're he's not my boyfriend, we're just on it, innit, just link whenever