2019-08-23 : Attacking with a goaded creature doesn't cause it to stop being goaded. It remains goaded as long as it's equipped with Bloodthirsty Blade.

2019-08-23 : Bloodthirsty Blade has no equip ability. There's normally no way to have it attached to your own creature, although certain combinations of other cards make this possible.

2019-08-23 : If a creature you control has been goaded by multiple opponents, it must attack one of your opponents who hasn't goaded it, as that fulfills the maximum number of goad requirements. If a creature you control has been goaded by each of your opponents, you choose which opponent it attacks.

2019-08-23 : If the creature doesn't meet any of the above exceptions and can attack, it must attack a player other than Bloodthirsty Blade's controller if able. It the creature can't attack any of those players but could otherwise attack, it must attack an opposing planeswalker (controlled by any opponent) or the player who controls Bloodthirsty Blade.

2019-08-23 : If the equipped creature can't attack for any reason (such as being tapped or having come under that player's control that turn), then it doesn't attack. If there's a cost associated with having it attack, its controller isn't forced to pay that cost, so it doesn't have to attack in that case either.

2019-08-23 : You still control Bloodthirsty Blade while it's equipped to an opponent's creature. You can move it any time you could cast a sorcery; the equipped creature's controller can't.