Best was four year age difference in my teens (me older than her), but I don't think I'm allowed to specify exact ages (it was totally consensual and we were both under 18, but still).
So far, the oldest was 8 years older. And I don't think I have ever been with someone younger. Even by a few months... Everyone I've been with has been older than me...
I had the unexpected pleasure of a young lady when clubbing a few years ago.
Really unplanned screw and I will tell you how it happened. I had been chatting for some time with married lady via a adult chat site and we had become very intimate friends without every meeting! Swapping nude pic's and daily arranging our chat sessions while our spouses were not at home (or in bed)
This all built up to an arranged meeting in our biggest city Auckland, she had heard of a swingers club and thought that a good place to meet. This club was actually a gay club for most of the time and held couples sessions every fortnight. All very different to our normal life and the meeting was planned a month before the eventual date. Unfortunately the day before the event she rang up and had to withdraw as her hubby's business trip was postponed - bugger - with all my excuses I had to make the trip anyway but she did tell me she had purchased entry tickets and I could use those so I did. The place was not really crowded and I was early because there was an international rugby game on TV and I wanted to be in to watch it. I had a good wander their were heaps of maze area's with glory holes, private rooms, a dungeon, spa, sauna and two video rooms one with porn and thankfully one showing the rugby. I sat on my lonesome watching the game. I would say there was about six couples and a number of blokes either chatting or wandering around. Halfway through the game a gorgeous young girl came to the bar with a terrific figure and a dress I will never forget, it was purple with big oval holes in varying sixes up the sides, they started small at the bottom of her tiny dress and under the armpits and gradually got bigger around the waist. Although it was reasonably dark it plainly obvious that she had nothing on other than that skimpy little dress. She was a cracker, while her partner looked a sleaze-ball a guy of about 40 with open shirt to the waist showing off his hairy chest and bedecked in gold necklace and wristbands - he looked like a pimp.
They watched most of the rugby opposite me and it distracted me from the game, while she kept changing the position of her legs I was always thinking he might get a glimpse of her snatch, but not to be. They got up and left and I stayed until the game was over.
I was probably the only guy over 60 there were a few young lads in their early 20's but most were between 30 & 50 so I felt a bit out of place. After a while in the sauna I moved to the spa and there was an older couple (50's) already there. I sat next to the woman and another young guy sat on the other side of us. Hubby was opposite and she then proceeded to play with my cock while presumably doing the same to the other guy. She obviously found what she was after with the other guy because all three of them got out of the spa and moved into the playroom area. Now I really felt left out so I thought I would walk around the maze area before leaving and I could hear coming right from the corner the obvious sound of someone fucking real hard. I found my way to the wall where the noise was coming from and could see light coming from a hole in the wall above me. Being 6'-2" tall on tippy toe I could just make out one of these young guys fucking away while standing in front of a woman with legs splayed wide and she was leaning back on this bed with another guy cradling her tits. It was very dark but very erotic watching this action with her pleading with him to go harder. He shouted dumped his load and strode out of the room witch let more light in as the door opened. I was just a quick right hand turn x 2 away from the door and ran as fast as i could to the door where the guy who had exited was boasting to his friends "my she fucking wanted it mate she is a bloody infomaniac"
The blood had rushed to my head and I had to get in that room, another guy beat me to the door so the two of got in. It was her the gorgeous girl without the purple dress! her partner was lying on this bed propped up against the wall and she was sucking him off while still bended over the bed with her back to us. I immediately started to lightly massage her backside, she was all sweaty yet her skin was so taught I let my hands work there way up to under her breasts and they were perfect so pert, sweaty and big with nipples protruding with both my hands working overtime on this young thing. The other guy just stood there and watched, eventually the pimp boyfriend said "out you go and shut the door on the way out" so he reluctantly left them to myself. He now instructed me to her fuck her real hard, hmm pity I was really enjoying my handiwork and her fanny was so wet and hot, it was steaming. My cock slid so easily into that hot honeypot, my hands continued to knead and play with her tits I would have loved to take my time but now she as well kept telling me to fuck her harder and harder. Of course I blew my load much earlier that I would have liked. I seemed to cum buckets squirting into that hot fanny for minutes I stood there not wanting the feelings to stop but eventually my little cock just slipped out. She immediately turned and started to suck me trying to get me hard again but I'd spent my lot and I needed time to recover. He was not so patient and said that's you lot out you go - bugger - I wish I were 20 years younger. She kissed me on the lips and said "thanks you were great some other time eh" I was on my bike the door locked behind me I had another quick spa, changed and left with a spring in my step.
Played around with a girl who is a couple years older than I am when we were teens, and got to taste and fuck the sweet pussy of a young lady who is four years younger than I in a "threesome" that didn't end well. That's a post for another day, though. lol