You don't need to tame it for it to produce Achatina paste. It will produce it in the wild on its own, so putting it in a pen close to water (wild Achatina needs to be close to water or it will die, as per the Ark wiki) will allow you to take advantage of this. Seeing as the paste is tough to see due to its size, it's recommended to build your pen on sand, or on any other terrain free from clutter.
Note that this has been only tested out on single player.
I've got four of these at my base and I've got way too much cementing paste so take note four is enough, but you probably also heard that they produce organic polymer which acts the exact same way as regular polymer except for having a spoil timer which is it's downfall. These don't produce very large quantities of this material however if you have a lot of it and you don't want it to spoil, turns out you can add it to their inventories on top of what they naturally produce and they will triple it's time left as an item - which works perfectly alongside something like a kairuku farm.
Hope that helps some of you, this gives me so much more time to get more polymer now and it even makes converting it to regular polymer through demolishing structures inefficient :)
Easy way to keep them in place, just fill their inventory with stone. Encumbered, they will not move, even on wander. Then for feeding, put cake in a tough. They will stay in place and alive! Making you resources the whole time... Up to the top for knowledge!
TIPP: Achatinas can produce organic Polymer. You can just craft a fridge with the organic Polymer and destroy it. Every time you destroy a fridge you get normal Polymer back. That means you can transform organic Polymer to normal Polymer. I found it out yesterday by myself.
You don’t even need to tame these guys to get paste, just pick a few up with a flyer and put them in a pen and overtime they will drop some paste but you have to remember to collect it or else it’ll decompose