More ways to measure a second. Wheel721 suggests the second could be defined as

“the time it takes for a 16 year old boy to cum after slipping his dick into his first pussy.”

Emma turns off the sink water, having finished the dinner dishes, and she hears the thump, thump, thump. For a moment she thinks it is the grandfather clock. The interval between thumps is so regular, about one second each. But that grandfather clock hasn’t ticked since the cat leapt on it almost a year ago. Emma dries her hands and steps across the kitchen and down the hall. In the living room, sure enough, the grandfather clock still slumbers. Alina’s bedroom door is open a crack. The thumping is definitely coming from in there. Louder. Thump, thump, thump, each a second apart. And each punctuated by a soft, sweet squeak. Emma knows that sound. It is the whimper Alina makes when she was being fucked, when she is a minute or two from orgasm. Emma eases the door open. Sure enough, there is Alina, up against the wall, and there is Nils, fucking her. Emma watches them. Nils hips driving forward. Pulling back. The gleam of sex juice on Nils’ big cock as it pulls almost but not quite all the way out of Alina’s cunt. The thump as Nils fucks forward, pushing Alina’s shoulders against the wall. Alina’s soft, sweet squeak. It won’t be long now. Another ten or twelve thumps should do it.

(Nils, as you can see, is no 16 year old boy. But he was once upon a time. Here below is perhaps a better illustration of the Wheel721 Second.)

One afternoon when Sheila’s parents are off on a second honeymoon in the Caribbean, Sheila invites her friend Nils over. “Look what I found hidden at the back of the bookcase,” Sheila tells him. It’s an old book. SEX faintly embossed on the cover. They sit on the living room couch examining the illustrations. “Look, this one’s called The Teeter-Totter,” Sheila points out. “Remember when we used to teeter-totter.”

“I think so,” Nils says.

“It was fun, but sometimes you bounced me til I had a sore butt.”

“I didn’t mean to,” Nils says.

“I think this teeter-totter might be even more fun,” Sheila says. “Want to try it out?”

“Really?” Nils says. Just having turned sixteen, he’s nearly a year younger than Sheila, and much less experienced. In fact, he’s had no experience at all.

“Not here,” Sheila says. “Let’s go down to the playroom.”

Once in the playroom, they take off their clothes, consult the book, and attempt to duplicate the position. Sheila, being experienced, is not at all surprised that exactly one second after Nils’ cock penetrates her sex, his ejaculation begins. She squeezes in time to the orgasmic jolts, milking the cock until the cum overflows her cunt, milking, milking until not many seconds later her own spasms arrive. The powerful clenching of cunt upon cock rejuvenates Nils. The young pair teeter-totter together long into the afternoon.