Full Ghillisuit, bug repellent, and balls of steel because these are scary to tame! They have the taming slot right behind their head about where the saddle would normally sit. Must approach from behind and only approach when feeding, stay away otherwise
Easiest and safest way to tame this is to lure it under water. They stop aggro and you can tame as you please. Just make sure you come up for air every once in a while. Also be sure the water is deep enough.
Once you apply bug repellent, have a ghille suit on and broth of enlightenment in your last slot. Sneak up behind it , you have to get really close to passive tame it. Aim for the back of the head, that's where the feed prompt appears. Good luck