This happened during my first year of university when I was 18.
I'd been at university for a few months and was living in a fairly large dorm. Some male friends and myself were hanging out trying to think of something to do when my friend suggested a panty raid. Everyone thought it would be a laugh so we formed a plan to steal all of the panties of as many of the girls in our social group as possible. The idea was to steal every single pair that they had so that they would be forced to either keep wearing the ones they had on or better yet go out without wearing any panties. Of course for this to work we would also have to find and steal any dirty panties they had in their rooms...
For the most part our task was very easy, hardly anyone in the dorm kept their door locked so we went to the rooms of girls who weren't in and emptied their panty drawers into separate bags and also located their dirty laundry and took the panties from that. We wrote the name of the girl on the bag with a marker so that we could return their panties to them later. The game got more fun when our target was in their room at the time, so we had to devise various ways of getting them to leave their room for long enough to grab their panties.
Within about an hour we had successfully gathered the clean and dirty panties of about ten girls, which were all bagged separately and put into a large black bin liner. Already knowing in my mind what I intended to do, I offered to hide the bag in my room where the girls wouldn't be able to find it.
It didn't take long for the girls to start looking for us asking if we had taken their panties. We denied it but weren't very good liars so it was obvious we were guilty, but we kept insisting it had nothing to with us. The girls retaliated by stealing the underwear from some of the guys, but as soon as we got wise to this the rest of us locked the doors to our rooms. This went on for the rest of the day until most of us went out in the evening.
When I got back to my room late that night I immediately got the bag of panties out from its hiding place and took out the individually named bags from within. I went straight for the bag with the name Kelly written on it, she was a gorgeous blonde girl with great tits and a perfect ass, and I had a major crush on her. I was still a virgin at the time and had never sniffed a girl's panties before but I was excited that I had something that would have touched Kelly's pussy and ass. I went through the bag looking at all her different panties, some of them were so sexy and it was so hot imagining her wearing them all. Remembering that we had also taken her dirty panties, I started looking for signs in the crotch that the panties hadn't been washed since touching her pussy. Soon I found some very sexy panties that had a dried white stain right where her pussy would have been touching the cloth when she was wearing them. I was so horny looking at this stain that Kelly's pussy had made, and I touched it and rubbed it on my hard cock, knowing this was probably the closest my dick would ever get to Kelly's cunt. As I was imagining licking Kelly's sweet pussy, I raised the panties to my mouth to lick her juice from her panties, and a strange smell filled my nose. My cock hardened to a rock as I realised I could smell Kelly's pussy, and man did it smell good. So musky and feminine, it made me crazy with sexual desire, and I instinctively took long, deep sniffs of the crotch and wanked my cock like crazy, thinking of her pretty face and perfect body. Very soon I had a powerful orgasm and my cum shot out across the room with huge force. I sat there for a while, hot and sticky, totally satisfied.
However, by the time I had cleaned up and put Kelly's panties back in the bag, I had pussy on my mind again, and my cock was hardening. I wanted to know how the other girls smelled so I opened the bag of another girl who I thought was really hot, and looked for the dirty ones. I went through several of the bags in turn, each of which had about three pairs that were dirty on average, but some had more. Some were very heavily stained, some hardly at all but they all had signs of wear. I looked at the name on the bag as I got to know how each of my friend's pussies smelled like. Some were disappointing and just smelled of stale pee, others smelled more sweet or creamy, but my favourites were the ones that smelled like Kelly's, a very musky sexual scent that made my cock rock hard and throbbing.
I was going through the bags in the order of how attracted to the girls I was, and I had almost been through them all when I got to Debbie's. She was a petite skinny redhead with freckles and very long hair. She was very pretty but not as obviously sexy as some of the other girls I knew, so I hadn't paid too much attention to her before. I found some panties in her bag that had very obviously been worn due to the stains in the crotch and had a good sniff. The smell was incredible! It was similar to the musky scent of Kelly's pussy, but very powerful and pungent and it made me go absolutely crazy. As I sniffed hard the smell was almost too intense and I could feel an orgasm building up inside me and nearly passed out. I only managed about two strokes on my cock before I exploded. When I ejaculate I normally shoot several short spurts of cum, but this time I swear I literally peed cum for several seconds in one long stream, followed by a few short spurts. The force of the orgasm made me take my hand away from my cock as it jerked uncontrollably, spraying cum all over the place. It felt incredible and it's still the best orgasm I have ever had by far.
The smell of Debbie's pussy was so strong that it lingered in my nose all night, and I left her dirty panties out next to my bed so I could sniff them and masturbate several times during the night. The next day at breakfast, while everyone was arguing about the whereabouts of their underwear, I looked round at all the girls, knowing what their pussies smelled like. I took particular interest in Debbie, and wondered how such an innocent looking girl could create a smell that drove me so wild, and wished that I could smell her pussy directly, and see if she tasted as good as she smelled.
I only had one more day with the girl's panties, because some of them had stopped finding it funny and were threatening to report us. I was sad to be giving them back, but I was now becoming slightly obsessed with Debbie, and knew that I couldn't go for long without the smell of her pussy. Over the next couple of weeks I spent nearly all my time talking to her, I would try to sit next to her at meals and would go to her room to hang out. A couple of times when I knew she was at a class I would go to her room, lock the door and find some of her dirty panties and jerk off. The danger of it was a real turn on.
It was pretty obvious to everyone that I was interested in Debbie, with people constantly making comments about us, and my friends teasing me. However she never seemed to notice that I liked her, so I thought she just wasn't interested in me. Then on a night out I was having drinks with Debbie and she began telling me how much she liked me. I was so happy and we spent practically the whole evening in the club kissing, and at one point we were in a dark corner and she let me finger her. It was a dream come true for me because I had been thinking about her pussy almost constantly for the past two weeks, and here I was with my finger inside it! When I slid my hand into her panties I was surprised how hairy she was down there, I had little experience at that time but even I knew it was quite rare for an 18 year old girl to be unshaven, but I thought this could possibly be the reason why she smelled so much stronger than the other girls.
At the end of the night she took me back to her room and I lost my virginity to her, which I'd love to tell you about but don't think it's allowed on this site. She did taste as good as she smelled though.
The next few months were bliss, we were having sex almost constantly and I had told her how much I loved the smell of her pussy, which she was embarrassed by to begin with, but eventually found it horny and we started to use her dirty panties in our sex play. I would also secretly finger her in public every chance I got, which would leave the strong scent of her pussy on my fingers, which I would sniff during classes.
I still have a major fetish for dirty panties but they are always such a disappointment after Debbie's. She has also left me with a fetish for hairy pussy and redheads, it's a shame they're so rare. She is one in a million, man I want her back!