Don't use a rocket to deal the final blow because the body will fly off the side of the map and you won't be able to get the element

The dragon is untamable. Period. You’re welcome.

To kill the Dragon, bring a decent amount of 100% inprint Rex’s (maybe around 10-20) a few friends, rocket launchers and guns and you will hammer the dragon or any other boss

An easy tame, bring a slingshot and mabye a a few narcoberries.