Panda sex: It doesn't have Series Archivesto last long. It doesn't have to be good. It just has to happen.

That's what matters to Totenko Co., anyways.

Totenko is a Tokyo-based restaurant company who's flagship location is "within walking distance" of the Ueno Zoo, according to Grub Street. And when pandas at the zoo love on each other, it can bean big business for them.

A 52-second affair between giant pandas Shin Shin and Ri Ri last week sent Totenko Co.'s stock up 2.9 percent--more than five times their three month average, according to Bloomberg--much to the quiet, gentle pleasure of stockholders.

Panda births see a massive increase in tourism and, in theory, Totenko's proximity to the zoo would guarantee it an increase in customers.

It's been four years since the birth of a baby panda at Ueno.

Pandas are notoriously ambivalent about sex: Scientific American says there is "perhaps no mammal that is less often in the mood for sex" than the female giant panda.

The mating window, rare as it is, lasts between 24 and 72 hours. It's like if you could only have sex on Memorial Day weekend, and even then, you're not guaranteed that your office gives you the whole thing off.

When a baby panda was born in 2012, there was an estimated economic impact of $89 million.

So yeah, you're gonna want to mark your calendars.