This is a passive tame creature. Meaning you cannot knock it out to tame it, it must be conscious and very much active to tame. By far the best method is to gather as many mejoberries as possible. After this, try to get to a non-hostile environment with the Diplo following behind. Then, stand under the breast of the animal (or right between its front legs) and just spam the Y button for Xbox (after placing the Mejoberries on the last slot of your hotbar) and just wait until it gives you the option again. The Diplo will not move unless disturbed by someone else. This Dino with a saddle is amazing for large and fast transportation of up to 10 passengers! With a decent amount of health too!
Know that it is easiest to passive tame them, which means walking up to them and feeding them
Get a TON of berries, everytime you feed it, it will go up like 3-5%
Have a high speed, high attack flying dino, (high attack in case you "miss click")
HAVE PATIENCE, diplo's are a stubborn tame, they will push you playfully (hence the flying dino)
MAKE SURE there are no carnivores around, if there are carnies around it will attack it there is a chance of it dying, it will get rid of all your hard work, and most importantly, IT MAY DIE (R.I.P. attempted tame #1 + 2 😢)
Plz note I am not an "high level player" that has a giga, I am lvl 50, (51 at the time I wrote this, almost 52) so I am not that experienced, tho I am sorta, I don't know that much about the game
Passive tamed a level 12 (+5 levels) with 15 mejoberries. If you can situate yourself under it’s legs, specifically between the two front ones, the diplo will continue to try and bump you back but will be unsuccessful. It will do this move over and over again, and drain its stamina and hunger faster, which leads to a faster tame.
I've tamed at least like 20 of these guys I started running out of names but the trick is to get under their belly so they try to attack u but can't then u feed them some stimberries so they get hungry then u feed them the food