Working on a world, but this isn't TOO annoying.
Load up the Jungle Temple template on Peaceful. Where you can put a seed in, instead click on the right arrow and select Jungle Temple.
Turn on coordinates and experimental gameplay. Knock out some wood, make a bunch of fences, a fence gate, an axe and a pickaxe. No go looking for pandas.
While you're looking for pandas, grab every bamboo you can get.
When you find a panda (if you're lucky, you'll find two together. That happens), fence it in. If you only got one, search for another one. Use bamboo to lure it back to the fenced area.
Make sure you have a lot of bamboo. In order to breed pandas, there must be 8 bamboo plants within a 5 block radius of the panda. (I planted 2 in each place so it looks like a taller stalk.) Once you've planted bamboo all over the fenced area, then feed the 2 pandas. If it doesn't work, plant more bamboo.
This achievement has a much-delayed pop, so even if you get it, it might take a bit.
From Davis 888 in the comments: Davis 888 said:
If you type in seed 2069597813 it will take you to a Jungle Temple world with a bamboo forest at coordinates 464, 64, 115. Make sure to turn on "Show coordinates" under settings and also "use experimental gameplay"
I didn't even need a fence as there were lots of pandas running around!
Best of luck!
PS. You can use the same world for this:
Find the jungle temple, dig the tripwires for the string, and use string and bamboo for scaffolding.