I think it might means your a virgin And the tattoo was a sexual outlet for you. Or maybe it means that and that since you are 18 its legal to get a tattoo and you did it to do something to piss off your parents and still keep the meaning of the tattoo, Or maybe its just a altered tramp stamp. Being as the tramp stamp is normaly on the lower back you just put it off to the side alittle to be different and orginal