My name is Andrew: I'm fifteen. I have a little-brother and little-sister: nine-year-old twins. We live in Texas. Since it's so hot all summer, if we're not leaving the house we don't bother putting on regular clothes: just undies and shirts.

Back when I was like twelve, my buddy Chris and I got to talking about jerking-off. I commented about how the cum I shot made such a mess and how it sucked having to clean it up afterwards. He told me that had he had found a solution to that problem: he wrapped a pair of his little sister's panties around his dick when he jerked-off.

Since Chris was always going on about how great it was so I decided to try it. For the first month or so I was just using my sister's. One day I accidentally grabbed a pair of my brother's undies out of the laundry and it worked just as well. Since then I've been using both.

I jerk-off into their underwear every day, at least once a day. My little sister wears pink Disney princess panties, and my brother wears Spiderman undies. It's so hot to cum into their underwear, but what's even hotter is putting them back in the drawer with the clean ones afterwards. Since all they wear are their undies and shirts, I can always tell when they're wearing the ones I recently cummed in.

For some reason I seem to shoot more and harder into my brother's undies. I get so hot picturing his hand wrapped around my dick when I'm using his undies. Don't get me wrong, I cum pretty hard in my sister's panties too. I've used their bathing suits as well: my brother's bathing suits are okay, but my sister's bathing suits are just perfect for it. Last summer she started wearing bikinis.

They've never said anything, but I'm pretty sure they know what I've been doing to/in their underwear. Quite often I see them wearing the ones I've just used and put back in their underwear drawers.

***

A little less than a year ago my sister saw me hard when I was getting out of the shower. She seemed kinda shocked and asked why my dick was hard. I told her that guys get hard when they're turned on and girls get wet, and she was just like "okay" and stared at my crotch for a few minutes then left.

About a week after my sister saw me getting out of the shower, my brother caught me jerking in my room. It was one of the rare times when I didn't have a pair of their undies wrapped around my dick. He just stood there watching as I pumped my fist up-and-down the length of my dick until I shot my cum. Afterwards he asked if it felt good: I told him it did.

They've caught me jerking-off a few times in the past couple months. Usually they just watch until I shoot my cum before leaving.

***

Since I'm usually home alone babysitting them all day during the summer, we have plenty of time if I decide to try to do something with them.

I wouldn't be surprised if they were playing with each other. They share a room, and they're very close. My sister is always either on my lap or my brother's, so if they played with each other I wouldn't be shocked.

Both of them usually just wear underwear and a shirt around the house. It's great when either of them sit on my lap. I always get hard, no matter which one it is. My sister usually just laughs and wiggles around and my brother will move around a bit, lean against my chest and hug me.

She sits on my lap in just panties, as does my brother. It feels nice, and I enjoy it. I've gotten hard under her and my bro more than a few times, and they both have the same reaction. They know what it means and they like to tease, so they move around on my lap, sometimes long enough that I shoot. No, I don't actually shoot my cum on them, the insides of my underwear end up being a sticky mess.

But, since Alice and Aidan don't mind me doing that, they might let me cum on them.

***

Lately my little brother has been touching himself, through his underwear, while he watches me jerk off. My sister just watches, and she just giggles when I shoot cum.

I usually give them baths together every night.

I decided to try something with them. I was filling up the tub and right when they got in I asked if I could get in with them. Alice seemed a little hesitant but Aidan said yes right away so she agreed to. I stripped down and got in the tub and I was already hard.

Aidan seemed more eager, so I started washing him first. I started with his nipples and went down, skipped over his dick and butt, washed down his right leg and then back up his left leg.

Once I got to his dick, the little guy was rock hard. I gently wrapped my fingers around it and began moving my soapy fist up and down its length. He moaned with just about every stroke I made and was thrusting into my hands. I took his dick in my mouth and reached around to rub his butt, and his dick stiffened slightly just before it started pulsing in my mouth, about two seconds later it went soft. He wanted to get out of the tub, but I told him he had to stay until I was done with Alice and myself.

I brought Alice over in front of me, and I started on her like I did Aidan: licked and sucked her nipples before washing them, kissed her while I washed her belly and back, then washed my way down her right leg and up left leg. When I got to her little pussy...wow! She was so tight I barely managed to get one finger into her, but once I did (after a lot of wiggling); we got into a good rhythm, she loved it. I sucked on her clit for a while. She came pretty quickly around my finger.

By then my dick was so hard it was literally throbbing. All they would have had to do to make me shoot my cum, was touch my dick. I took a deep breath and relaxed for a moment before I asked my little sister to touch me. Once again, she was reluctant, but after a few tense silent seconds she hesitantly reached out, wrapped her little nine year old fingers around my dick and started stroking me while Aidan watched.

I picked him up and kissed him while Alice worked my dick. When I was about to cum, I had Alice stop stroking my dick. I replaced her hand with mine and stroked pretty fast. Barely a second later the biggest load of cum I've ever shot, spewed out of my dick all over both of them.

Alice was a little shocked; Aidan actually seemed to enjoy it. I licked some of the hot white cream off him, then told him to try it. He loved it, and licked it off Alice too. After that, I put them to bed, and then our parents got home.

***

Neither of the twins said anything, and they still haven't. That's become a bath-time ritual when our parents aren't home. Alice now loves it just as much as Aidan.

I haven't had sex with either of them yet, but I want to: who knows maybe it'll happen later this summer...