my girlfriend and i are both 20. last week, while making out, i was nude and she was in her panties. we were kissing and in the process, my naked penis rubbed against her underwear twice. i am sure that i did not ejaculate. she was wet but she had her underwear on all the time.there was no direct contact with her vagina. and also, i am not sure if there was any pre cum present on my penis too. even if there was, it would be just a drop. and i just rubbed against her twice, and we didn't go any further. she was having her underwear on all the time. so what do you think are the chances of pregnancy? Zero? Or can one stray drop of precum pass through her clothes, move into the vaginal opening and get her pregnant? It was on the 7th day after the first day of her periods. And this was the first ever "sexual" thing that we did, as we were carried away. We are not ready for pregnancy, and both are very scared. Please explain the odds clearly