Ark Logic at its fullest:

Find a nice fasola house, bomb his home until he comes out and is dazed. Then jump on his back and crack his head into rocks until he is asleep. (Knock some sense into him) Then while he is asleep shove meat down his throat until he loves you and will risk his life for you.

Makes perfect sense

To knock it out, use any sort of explosive (Grenades are cheap and have early unlock) and throw it at the Fasola while it's underground. It will look like a pile of sand and shouldn't react if you go up to it.

As soon as the explosion goes off, run up to the Fasola and mount it. You only have a few seconds to do this. Once you're on, try to find any nearby rocks/bones/etc and run into them. Every rock you hit will increase torpor and control. If control runs out, you will be dismounted.

DO NOT GO ON CLIFFS !! If the Fasola goes into the air at all, you will automatically dismount and lose all progress. Depending on your rates, it could take a long time to gain enough torpor.

TL;DR : Explode it, mount it, hit rocks, avoid cliffs.

-OtterWithATophat :D