This reflects my early years in the world of sexual excitement. The fact that my experiences were with my brother is not surprising. I think many sexual awakenings happen at home. Note that in British English 'knickers' is more often used. It has a certain 'naughty' ring to it. 'Panties' and 'briefs' are used too, but in shops etc.
I made my confirmation in the Catholic Church and I started getting my periods then and had picked up from others girls at school a lot of information about sex. For my confirmation I wore the usual white dress and veil but Mom also bought me new modern underwear, nice white nylon knickers and vests. This was when girls started wearing their skirts and dresses short. My school girl friends and I enjoyed letting boys see our new fashionable knickers whenever we got the opportunity, but it was at home that I felt more comfortable doing this, with my brother who was two years younger than me, even though I didn't think that he was very sexually aware then. I loved bending down to pick something up in front of him, or when sitting down, bringing my knees up so as to let him see the crotch of my knickers pressing against my pussy. Other girls had told me that this was a sure way of giving any boy an erection or as we called it then a horn. I often asked him to help me do hand stands when no one else was around. This meant that my dress fell down about my chest exposing my panties completely and my brother would hold me around my waist with his hands on the panties. I especially liked it when his fingers would just slip inside the plastic band of the knickers. We never said anything about what we were doing but as I recall the animated almost breathless talk of both of us clearly indicated excitement and arousal, and my brother's erection showed clearly through the front of his pants.
I had heard from girls at school that some boys used girl's underwear to get themselves off with, and as I had noticed, when I was just eighteen, that some pairs of my knickers would go missing for a while and I suspected my brother. I waited until one day when no one but he was at home. I crept up to his room and opening the door was about to ask him for a favourite music tape of mine. He was stretched on the bed naked but for a pair of my yellow nylon panties which he had pulled down just to the top of his thighs and he was holding what appeared to me to be his enormous erect organ. His eyes were glazed over, but he didn't move.
Before I approached his room I had been thinking of him masturbating with my knickers, so I was quite aroused and feeling wet even before I saw him. My knees at this stage were weak. I propped myself against the door and slowly raised my dress. I had white nylon, almost see through knickers on. I started to rub my pussy though my knickers with my right hand while my left kept my dress up. I then took hold of the elastic band of my knickers. 'Do you like my white knickers as much as the yellow pair, Tony?'. 'Yeah', he said, as he stroked his tool up and down. 'If I take them down you'll see my pussy. Do you want that?''Yeah, please Regy', and there were tears in his eyes. I edged down my knickers and he drew a sharp breath when he saw my pussy barely covered in light blonde hair. I inserted two fingers and started to climax. Tony's breath started coming hot and heavy. I pressed my fingers into my pussy pretending they were Tony's huge organ pumping inside. Tony was muttering as if he were raving in a fever. 'Regy, look at me, I'm wearing your knickers, I can't help it, I love my beautiful sister, I love wearing your knickers.' I was in a state of collapse, almost, against the door, as an orgasm shot through my whole body and I could see Tony's spunk shoot over his belly and chest.
After a while, I got up, pulled up my knickers and smoothed my dress down. I went to the bed and pulled the lemon coloured knickers up over Tony's shaft that was still big but had gone soft. I massaged him though the slinky material and his erection grew. 'Come on Tony, I'll help you. Lots of boys like to wear their sisters panties. I want you to spout it out for your sister. Come in your sister's sexy panties. I love your soft balls and hard prick. Come on, Tony, soak my panties with your spunk'. Then my brother let out a deep hollow breath. I pulled the top of the knickers as far as his navel and then his spunk came out as if out of a tap, much more this time. 'Good boy, good brother, Tony. You must always wear my knickers, they will always keep you hard.'
For many years afterwards I'd slip a pair of frilly knickers in his jacket or suitcase. I still do, though we are both married with grown up children. I can still imagine when I masturbate that glazed over look and short breath of my brother as he is about to cum in my panties.