Back in the era of my puberty, we didn't have these fancy Internets. (Actually, we kinda did, but I didn't have one in my room.) And I was both a Good Girl and a somewhat unpopular one. I didn't have any access to porn in any form. I had a couple novels with steamy scenes, but they were of the annoyingly vague "she felt a white-hot light radiating from his body as her head soared through exploding stars" variety--no details, man.
But, my mom being a nurse and my family generally scientifically inclined, we had lots of textbooks. Biology textbooks. You see what I'm getting at here.
"Among both sexes, the excitement phase results in an increase in heart rate (tachycardia), an increase in breathing rate, and a rise in blood pressure. An erection of the nipples, especially upon direct stimulation, will occur in nearly all females and approximately 60% of males."
"During the plateau phase, the male urinary bladder closes (so as to prevent urine from mixing with semen, and guard against retrograde ejaculation) and muscles at the base of the penis begin a steady rhythmic contraction. Males may start to secrete seminal fluid and the testicles rise closer to the body."
OH BABY OH WOW
"Orgasm is the conclusion of the plateau phase of the sexual response cycle, and is experienced by both males and females. It is accompanied by quick cycles of muscle contraction in the lower pelvic muscles, which surround both the anus and the primary sexual organs. Women also experience uterine and vaginal contractions. "
OH YEAH OH YEAH OHMYGODOHMYGODDDD
The upshot is that I accidentally became very well educated on sexual anatomy and physiology at a very young age. Not just the obvious parts; being a very thorough reader and rereading the same three pages for months, I learned all the little internal bits with Latin names as well. I'm taking an anatomy class right now and I'll have to study the liver, I'll have to study the lungs; I've got the penis down cold.