My name is Andrew. I'm 15, and I have a little brother and little sister, twins age 9. We live in Texas, so it's hot all summer and all they wear are their undies and shirts.

I jerk-off into their underwear all the time. 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 more hot is put them back in the drawer afterwards. Since all they wear are their undies and shirts, I can always tell when they're wearing the ones I came in.

I probably come harder into my brother's undies. I get so hot picturing his hand wrapped around my dick when I'm using his undies. I do come pretty hard in my sister's panties too. I've come in their bathing suits as well. My sister wears hot little bikinis that are just perfect for it.

When I was like 12 or 13 I had a buddy who would do it with his little sister's panties. He was always going on about how great it was so I decided to try it. At first I was just using my sister's, but I accidentally grabbed a pair of my brother's undies out of the laundry one day and it felt great, so now I use both.

They've never said anything, but I figure they must know because I see them wearing the ones I've used and put back in their underwear drawers.

My sister saw me hard when I was getting out of the shower once. She was kinda shocked and asked what it was, so I told her, and she asked why I 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 me for a little while longer then left.

My brother caught me jerking in my room once. He just watched me for a few minutes until I came and then asked if that felt good: I told him it did.

They've caught me a few times since then, and they usually just watch me.

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 come...no, I don't actually come on her, I come in my pants. Although, since Alice and Aidan don't mind me doing that, they'll 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 trusting 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, then 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. All the while kissing my way down her body. When I got to her little pussy...wow! She was so tight I barely managed to get a finger in her, but once I managed to (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 throbbing so hard, all they would have had to do was touch me to get me to cum. I took a deep breath and just relaxed for a minute or so before I asked her to touch me. Again, she was hesitant, but she hesitantly reached out, wrapped her little 9 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 enjoyed it more than she did. I licked the come off him a little, 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.

Niether 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...