My sister, Laura, and I were talking, and as was becoming the
case quite frequently, the subject was sex. Our discussions had
of late been speculating about how it would actually feel. I
made my comment half in jest and half seriousness when I
suggested we try it with each other to see what it felt like. I
did not expect Laura to agree. True, I would have given my left
nut to fuck her. Laura is cute as a button, with shortish blond
hair, blue eyes and a five foot three inch, one hundred five
pound body. I was only half serious, though. I was certain
Laura wouldn't actually do it with anybody, let alone me, her
own brother.

Her reaction was definitely not what I would have expected. I
knew she wouldn't be angry, but I expected her to throw a
pillow, or something like that, playfully telling me. "forget
it". Laura, though, got a somewhat serious look on her face and
seemed to be thinking it over. "I don't know, Larry," she said.
"What if I got pregnant? I'd really like to, but wouldn't it be
risky? What if we got caught?"

My pulse became rapid and my dick got hard as steel, hearing my
cute kid sister say she'd actually like to do it with me. I
immediately realized that she might actually do it with me if I
could get past her fear of someone catching us and her worry
that I might knock her up.

I tried to act cool and suppress my eagerness. "Mom and Dad
won't be home for at least two hours," I reminded her. "As for
you getting pregnant, there shouldn't be that much risk. The
chances of a girl having a baby from doing it just one time are
actually pretty small. We should be okay." I only hoped I
sounded more confident that I actually was.

Laura thought some more and replied, "Do you really think we
would be okay? I'd really like to do it with you, but I'm not
sure." I knew then and there I would fuck her.

I asked, "When was your last period, Laura?"

My sister tilted her head back, did some silent counting and
replied, "I started two weeks ago today."

I'm no expert on girls' masturbation and fertility cycles, but
I do know it's supposed to be safer when she is close to her
period. "Well, we should be safe," I responded.

I tried to act completely sure of myself. When my sister
replied, "Well, I guess we could do it just this once," I nearly
came in my pants.

Laura and I got undressed and got on my bed. I'd learned from
my friend, Kenny, when he deflowered his cousin a month earlier,
that Vaseline rubbed on a guy's prick helped provide lubrication
when entered a girl with an unused and tight pussy. I'd
retrieved a jar from the bathroom and rubbed some on my hard,
stiff cock.

We were too self conscious to kiss, but I did suck Laura's pert
little titties and I even licked her slit. When I thought I had
her hot and wet enough, I slid up her body. For a little bit it
didn't feel like was even going to get it in. Her hole just
didn't seem big enough. Ever so slightly, though, I worked it
up inside her. I had to take it very slow and easy, as Laura
did say it was hurting somewhat. Finally I got it all the way
in. When I did, I went off immediately. The feel of my
sister's hot, tight pussy holding my clock like a vise, and the
thought that I was getting laid for the first time, was too much
for me. As I blew my nuts off in my sister, I wondered if she
was in her fertile time of the month. I realized if she was
ovulating I had probably just knocked her up. That thought was
both scary and very exciting.

Having spent my load in her, I began hunching my still hard
prick in and out. Lubricated by my slick sperm in her pussy, my
cock began sliding in and out. I felt like a real man when I
felt Laura shudder in her first orgasm, just as I blasted more
gobs of my baby gravy up her snatch. When I pulled my
softening, gooey cock out of her, Laura cuddled up tight to me.
"Hold me Larry. Hold me in your arms." I fucked her again
before the folks got home.

I was really surprised later that night, after everybody had
been in bed for a while, when my sister came into my bedroom.
She stood beside my bed and I watched her in the moonlight
coming through the window as she removed her gown and pulled off
her panties. I slipped off my pajama bottoms as she did. Laura
crawled under the covers with me and said, "Do it to me again,
Larry. Okay?" I fucked her in my bed. She cuddled up to me
for a while before getting up, putting on her panties and gown
and going back to her room.

It's amazing how Laura has taken to sex. I've never asked her
for it since. I don't have to. She initiates it. If our folks
go out, she immediately wants me to fuck her. She comes to my
room every single night. My sis is an easy comer and I always
get her off before I shoot my cum in her. I popped her cherry
just over three weeks ago and we've not missed a day since. I
was expecting her to tell me last week that we would have to lay
off a few days because she had her period. That did not happen,
though. Laura has not said anything about it, but if she was
correct about when her last period occurred, I think her period
is about a week and a half late. I haven't said anything to
her, either, but I'm beginning to wonder if I've knocked her up.
My suspicions are even stronger because I've noticed her heading
for the bathroom and throwing up a few times recently. Those
episodes happen in the morning. If Laura suspects she is
pregnant, she sure has been keeping it to herself, though. Her
prime focus with me has been for me to keep fucking her, and I
intend to do just that. I love my sister and, even more, I love
fucking her. I just wonder if I've made her pregnant. I may
write you again in the future and let you know.