Best tip you wil ever need.
Fill your inventory with so much poop you like. Then put the beetle on aggressive, and release it. Now let it kill you. When you respawn, claim it and it will have taken ALL the poop.
Upvote for people to know!
Get yourselves a Phiomia as well! Feed it stimberries and you'll have plenty of medium feces to throw in the dung beetle. Fill it up, and come back and watch more fertilizer than you can imagine. I'll never use compost bins again!