the family rule growing up was that if you couldn’t be bothered changing into swimwear to use the pool you could strip off and dive in in your underwear

about the time i became sexually interested in women my sis decided to stop wearing underwear in the pool and start wearing a swimsuit which was really annoying, especially since she hardly ever wore a bra and opted instead for a white singlet, which i knew would be like having a private wet t-shirt contest

i meanwhile only wore white cotton undies, which i kept swimming in, and which would go completely see through when wet

when we were both 16, mom and dad went out of town for the night and left us at home alone

i was taking a bath when i heard my sis come through the front door, she called out my name and i yelled back that i was in the bath, she said that she needed to talk to me

i heard the door open and she asked if i was decent, i replied of course not, i was in the bath, naked, but if she needed to come in she could throw me some undies, and it would be just like we were in the pool

some undies came flying through the door and landed in the bath and i slipped them on, telling her i was decent, she came in the room

so she sat down on the edge of the tub and started talking to me about something (can't remember what it was now) and after a few minutes her hand lowered down into the water

i don't think she even noticed what she was doing but she was running her hand back and forward through the water and every so often she would rub her fingertips against my cock

i was starting to get turned on and was "pitching a tent" in my wet white briefs, my cock was standing up so far the head was now out of the water and only covered by the wet see through material of my boxers

after another couple of minutes she looked down and saw my hardness and made some comment, i told her it was her fault as she was rubbing against my cock but she claimed it was an accident

then she looked back at it and remarked that it was a lot bigger then her boyfriends, and started poking it with her finger

i didn't really know what was going on so i grabbed her and pulled her in the tub still wearing all her clothes, black knee length boots, jean skirt, and blue and yellow checked cotton shirt

we started having a tickle/wrestling fight like we did as young children and were rolling around in the bathtub, it didnt take long for all of her clothes to get completely soaked

after a few minutes i was on top and i reached down and ripped open her shirt, and thankfully she had worn a singlet underneath, and it had gone completely seethrough

i started rubbing her tits through the wet material and when she didn’t object i pulled down her top and started motorboating my twin sister

she still didnt object and now i was running my hand up and down her legs aswell, i kept rubbing higher, until i was under her skirt and feeling the wet material of her panties

before i know it my head was under her skirt and i was kissing/licking her pussy through her wet panties, i slipped her panties aside and started fingering/licking her

as i had only been with one girl i was pretty incompetent but she seemed to enjoy herself and was grabbing hold of my hair and moaning

after a few minutes she must have cum as she relaxed and let go of my hair, then she told me to stand up

she knelt in front of me and started stroking my cock through my wet undies, then she pulled them down and took my cock in her mouth

i didnt last long before i blew a massive load all over her face and hair, i leant back against the wall to recover and she started to wipe my cum from her face, lick her fingers and swallow my juice

she got to my cum that was in her hair, but i told her to leave it there

we climbed out of the bath, stripped off and dried off then i went to my bedroom, put on some pajamas and went downstairs

my sis arrived a couple of minutes later also  in pajamas but with my cum in her hair, we were both a bit shocked i think and sat down and watched a movie and didn't mention what had happened

that was until the next morning when over breakfast she brought it up

i told her how sexy she had looked in her soaking wet clothes and how i thought her pajamas would look sexy wet aswell

so i picked her up in her pink silk pajamas, carried her out to the pool and jumped in

i told her to climb out so i could see how she looked, the material had turned pretty seethrough and was painted to her tits and stomach, it was also clinging to her pussy and revealing a large cameltoe

i asked her if she wanted to go a step further then the night before, and she said she would but she wanted to do it right

she appeared a few minutes later dressed as a french maid (i later found out that she had found the costume in my moms wardrobe)

she dived into the pool and we kissed then i carried her over to the shallows (water was just above her stocking tops) and leant her against the pool wall

lifting her skirt i found she was wearing crotchless panties, so i pulled down my pajama pants and slid in

we spent the rest of the day in and around the pool, every couple of hours she would go into the house and come out in a different outfit, and everyone of them ended up being ripped off and floating around in the pool

that evening we worked out we needed to wash and dry a few loads of laundry and when my parents returned the following day they were none the wiser