The origin came from skateboardings all accidents when you fell on the ass, and the word assplant came upp naturally. Then it became a thing to jump around and "plant the ass" on different kinds of thing.
Or if you accidentally fell, you can say you made a assplant.
Although the exact form of an assplant has not been confirmed yet, we can take this hint as all the evidence we need for the existence of the assplant (Even though the crazy irish man was drunk at the time)
This can be used as an insult, "You're an assplant!" reffering to someone who sits on plants and enjoys the experience, certain clubs of "Assplanters" have formed in several country towns in Ireland.
"You're an assplant!"
"That guy over there, he likes to assplant!"
Assplant grower, "Why yes, it's your lucky day. Now, with Assplant, you can get an incredible ass with only a couple minor implants!"