For this, you'll have to tame either a Pigsy, Night Hoglet or a Night Pigsy with a Taming Collar (craft it in your Crafting Menu - to be opened by typing "q" as the default key), equipping it and aiming it at a Pigsy for 10 seconds or at a Night Pigsy or Night Hoglet for 15 seconds.
Stun Bombs, taming from a ladder at the right distance or across a gap from a platform can help with that, as these Creatures will all fight back when being tamed and might sometimes push your player character away in the process. Night Hoglets are the easiest to tame as they do not inflict much damage and their pushing force is weak as well.
Then you'll have to feed your Pet, whereby you should try to feed it it's favorite type of Food which will be displayed in the Pet Window (activate your Pet by clicking it with the right mouse button). Some Pigsy types are content with only a Red Mushroom and some Night Hoglets with only a Brown Mushroom, so you might want to tame several Creatures until you find a modest one that's "cheap" to feed.
Afterwards, wait until the Pet is ready to be harvested and will display a Power Cell in its thought bubble. Then you can pull the Pet with your gauntlet (you won't even need a Power Cell equipped) just as if you were digging a block - hold your left mouse button while looking at the Pet.
After harvesting, do not forget to wash your Pet. Equip a Washer (to be crafted too) and hold left click again while aiming at your Pet to hose it.
Pigsy Droppings cannot be looted from Pigsies when killing or dismissing them.
These droppings can be used as fertilizer to grow Crops faster when Farming. To use them, put (a stack of) them into any of your quickslots, select that slot by typing its number and click your right mouse button while aiming at the Seeds or Seedlings that you want to fertilize.
Mind that you do not need to fertilize Seeds to make them grow, as fertilizing merely will shorten the time crops need for growing.
Fertilized Seeds (right after planting) will grow into seedlings immediately (which would usually need ca. 10 minutes for Wheat for example), and fertilized Seedlings will grow into Sprouts quicker than without fertilizer.
Wheat grows fastest (ca. 50 minutes) without fertilizer, Crisphead Lettuce and Turnips will need approx. 60 minutes, Horned Melons would need 91 minutes to fully grow without any fertilizer. These are the only 4 crops you can currently grow in Creativerse.
You also can fertilize tree-Saplings to spurt their growth if they are not fallow - if you planted them in the correct biome not too far from water (mind moisture does not need to touch the block with tree-saplings on it directly, which is necessary to grow crops).
You cannot fertilize fallow Seeds (which you can see written in red letters at the bottom of your screen if you look at the seeds), you cannot fertilize Sprouts (the third stage of growth directly after Seedlings), and you also cannot fertilize any crop more than one time (so once a Seed has been fertilized, the Seedling growing from it cannot be fertilized as well).
Crops all grow in real-time (even when you're not in the game), so sleeping on a bed ingame will not make crops grow faster.