The chance of pregnancy from the situation you describe is highly unlikely – but not impossible. To put this in perspective, let’s first describe the ideal situation for getting pregnant. Conception is best achieved when the penis is positioned inside the vagina during ejaculation, and when the woman is at the most fertile stage of her menstrual cycle (the days shortly before, during, or shortly after ovulation). While finger sex has a very low risk of pregnancy, you can make sexual exploration much safer for your girlfriend by washing your hands after asturbating. Use soap and water or generous amounts of hand sanitizer. This will also help reduce the chance of spreading a sexually transmitted infection between partners.