Can someone's dna remain in other person's body by fingering? if yes, for how long? will that different dna disappear from the individual's body?

STD risk?: Presumably this means you're worried about STDs, right? STDs ever are almost never transmitted by fingering or other forms of hand-genital contact, only by intercourse or oral sex. But if you're concerned, see a doctor to get checked. And even if you're not yet having intercourse, it sounds like you're getting close. Please get on birth control (if you're female) and also have condoms handy.