Sherlock x Reader: You Bleed Where?

Blood.
Blood everywhere.
You cursed as you took your towel to wipe the running crimson streak down your leg.
Every. Single. Month.
You hated having to bear this stupid hormonal crap called a period. It was horrible having to go through it for an entire week. Mood swings, unusual food cravings, and the fact that you were tired all the time didn't help at all.
Walking out of the loo in an oversized t-shirt and sweats, Sherlock caught your sleepy form. He had no idea why you were so tired and cross all the time. A cramp seared through your stomach, causing you to stop and clutch it in pain. Luckily, you were used to this kind of thing, and knew it would pass in a moment. Sherlock, however, didn't, and rushed to your side to help you to the couch.
"(YN)? (YN), are you okay?" he asked as he sat you down and studied your actions. Your face was a little pale, and you were absolutely exhausted. "What's wrong?" You shook your head as the cramp pain passed and you sat back.
"I'm fine, Sherl, I'm used to this," you assured him, hand resting on his shoulder. Worry flicked through his eyes. Then the realisation set in.
"Is it the time of month again?" he asked, hoping you would say yes. A blush formed on your cheeks as you nodded, and Sherlock immediately relaxed as he flopped back next to you.
"What's it like?" he asked suddenly. You had an idea if what he was asking.
"You mean my thing?" you reiterated.
"Just for future reference." You sighed.
"Well, I get mood swings, and sometimes I get food cravings. Not to mention I'm always exhausted." He looked at you, knowing that you weren't telling him exactly everything.
"What else?" he pressed.
"Well..." you said, trying to think of how to explain it. "I sort of... bleed."
"What, how? How do you deal with bleeding for an entire week?"
"Sherlock, I have been doing this since I was a teenager." He opened his mouth to say something until you winced at another cramp. In an attempt to make you feel better, Sherlock rushed to the kitchen to get you both tea, hoping it would ease at least some of the pain. Walking back into the living room with two steaming mugs, he still had one question unanswered.
"Where exactly do you bleed?" he wondered as he handed you the tea, still standing.
"You really want to know?" you asked him cautiously. He nodded and took a sip of his tea.
John walked up the stairs to 221B, fully aware that he knew he shouldn't provoke you into anything. Being a doctor, he expected all your symptoms. The only thing he didn't expect when he opened the door was Sherlock's incredulous shriek:
"YOU BLEED WHERE?!"