QuestionI am pretty sure that my period will begin within the next few days. I was visiting my boyfriend and he pressed his naked genitals up against mine, harmlessly. He was releasing the clear fluid before ejaculation, but because I was a little nervous, I refused to let him get too close to the vaginal opening. Now, I know it is possible for the clear fluid to contain sperm, so my question is: what is the chance of pregnancy?
The chance of pregnancy is very small, but it is not zero. The chance of passing a sexually transmitted disease is much higher because many of them can be passed by skin-to-skin contact or by fluids. Since he was sexually aroused and producing pre-ejaculate fluid, if he had a disease, it could be passed to you as the fluid contacted your skin, especially if there were any wounds (even minor ones). Nor does the fluid have to reach your vagina directly from his penis. If he got some on his fingers and put his fingers in or near your vagina, that can bring sperm into your body as well.
The real question is why are you and your boyfriend exposing your genitals to each other? While you managed to keep his penis out of you so far, it won't always be the case. You call what you did "harmless," but since when has sin ever been harmless? Even if you manage to avoid disease or pregnancy, harm still took place in your spiritual life.
"But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart" (Matthew 5:28). Even though you kept his penis out of you, he was thinking about having sex with you. Thus, even though you didn't commit fornication at that time, he (and you) were as guilty of fornication as if you did have sex.
In addition, you are both guilty of lust. ""For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust, like the Gentiles who do not know God" (I Thessalonians 4:3-5). Instead of thinking of you as a young woman to be admired, you got him seeing you as an outlet for his sexual urges. How is that going to build a lasting relationship?
You both need to repent of your sins and stop fooling around with each other's body. It isn't a game to see how close you can get without crossing "the line." You already crossed it.