Mine's less about me and more about the girl: Was with this feisty redhead for like 6 years. She was a borderline nympho at times and liked being tied up. There'd be instances where she'd have multiple orgasms, but it topped out at like 4 or 5 at the absolute most. She'd usually be ready to fall asleep after the first or second, so not much else happened in general.
Well this one time like two years into the relationship, I tied her hands up and was going down on her and she got really into it and went into this Killer Instinct style auto-combo of having orgasm after orgasm. I wasn't doing anything out of the ordinary and she was coming from me barely doing anything sometimes. I kept expecting her to tell me to stop and she didn't, for whatever reason it just kept going and she wanted more. Then we had sex all over the apartment (interspersed with oral, rubbing, whatever, I kept changing it up) for like 2-3 straight hours and she lost count of all of her orgasms. She stopped counting at 18 and thinks it was somewhere in the mid-20s or higher.
This never happened again. I'm not sure WTF it was, aside from her just being really, really worked up at the beginning?
I don't even remember if I came more than once myself. I was too busy trying to see how high of a score I could rack up because she was losing her mind. I plowed her in bed, on the kitchen counter, in every room, in front of some of the windows with her smashed up against the glass (we lived on the fifth floor of a building downtown), in the shower, and back in bed, until we were both like completely spent.
Another fun thing we did a few times was when we'd both be in the mood, but she'd forbid me to touch her for X amount of time first. I remember watching Game of Thrones with her and having her slowly dropping clothes on the floor one at a time as the episode wore on, with me not allowed to touch her until the end credits. So I'd be trying to focus on the show and she'd be like writhing around next to me on the couch with nothing on, like an inch away from me, tossing her red hair around, until I started to lose my fucking mind. Whenever time would be up and I'd be allowed to touch her I'd jump on her and we'd have the most amazing fucking sex I ever had with anybody. I highly recommend trying something like this.
Most of my best sex memories are with that one girl (we're still friends).