My sister and I have this very special relationship that only brothers and sisters can have. She was always a shy nervous girl where everything and anything would scare her, a storm, a loud noise or even a TV programme would cause her to bust into tears and run and hide. Quite often she would hide in my room and I would search her out and give her a big cuddle. The years didn't lessen her fears just added new ones and more and more she would spend her time with me in my room. I now had loads of homework to do every night and she would keep me company and even help especially with my spelling.

I was working on my English homework and she was lying on my bed reading a comic when mum poked her head around the door.

"I'm off now, ok, don't wait up" she said, for she works late in a bar around the corner.

"Ok mum," we both chorused.

The front door slammed and we were alone in the house. I was concentrating on my work when I hear her sniffle from behind me.

"What is it sis?" I asked turning around.

For many minutes she just cried so I went to sit beside her on the bed.

"It's Frank Slater," she sobbed, "he wants me to give him a blow job."

"What!" I exclaimed, positive that I must have misheard her.

"He says I have to suck his dick or he'll hurt you," she sobbed.

"Hey, hey," I soothed, taking into my arms and for not the first time I found that she was no longer that scrawny thing I once remembered.

"Don't you worry about Slater," I said, "I can handle him."

Well I knew I could never take on Slater and win for he was the biggest bully in the whole school but I knew one thing I could hurt him before he flattens me.

"It's not just that," she sobbed, "I have these feelings that scare me."

Well nothing new in that, I thought.

"It's like some part of me wants to suck his dick," she sobbed, "even someone like him."

"Look sis, it's all part of growing up," I explained, "you will have these feelings and urges but please direct then at some one more worth while."

She clung onto me and I could feel her small tits up against my chest.

"I could suck your dick," she said in a small voice.

"Don't even think like that," I said a bit shocked, "you my sister and things like that are not allowed."

"Why?" she asked pulling back and looking me directly into my eyes.

"It's a genetic thing," I tried to explain and thinking back to my biology classes, "you and I have similar genes and if there's a rogue gene we probably will both have it so any offspring we have may come out deformed."

"That's stupid," she laughed, "even I know you don't get pregnant from a blow job."

"No of course not," I said feeling hot, "but it's the same principle."

"Well that's stupid," she said, "if I want to suck your dick I can't see any reason not to."

"Ok let's drop it shall we," I said.

All this talk of her sucking my dick was having an effect down below.

"It not only that of course," she said totally ignoring my last comment, "I want to do other things too, I have this itch down there," she indicated with her hand towards her groin, "and I even look at the bulge in Slater's pants."

"Look sis, this is all perfectly normal for a young girl like you," I explained, "and for boys too. Your body is growing up and wants to mate and have offspring, that's what it does."

"But why do I look at Slater when I find him so repulsive," she asked.

"That simple sis," I said, "you are the end result of 4 billion years of evolution and the hard wiring in your brain is looking for the best mate so your children will be fitter and stronger than the competition, so you look for the strongest male."

"Yuck, I rather do it with you," she said.

"This is all at a very deep level," I explained, "it's why guys like big tits, plenty of milk for their babies so they will grow big and strong."

"I knew there had to be a reason," she laughed again, "must be bloody uncomfortable for the poor sluts though."

I was pleased that she had cheered up but that still left Slater to deal with.

"I hear that you going to hurt me," I said to Slater catching him on his own for once.

"What," he said surprised, "way would I want to waste my time on you."

"The way my sister tells it," I said trying to look relaxed, "you've been hitting on her."

"So it's not a crime is it for a guy to hit on a pretty girl," he snarled.

"It fucking should be with you," I said feeling more confident now, "so I'm telling you now, make your move on me or leave my sister alone."

"Are you going to stop me?" he asked belligerently.

"Of course," I smirked, "oh I won't fight you fair, I know I can't win that way, I'll wait until you're vulnerable, attack you from behind, I'm not fussy just as long as I hurt you bad."

I could see he didn't believe that someone would stand up to him and especially not me. His brain was turning over slowly, accessing his chances and he didn't like the odds.

"Your fucking barmy," he laughed and turned away.

I didn't know if that was the end of it, only time would tell, but from now on I would have to remind him sometimes on how vulnerable he can be.