Medieval Dynasty

As the description says, 4 spears in an animal, while it's still alive.

I changed my settings to aid in this.
Under Customise Game change the following settings

Unlimited stamina - On
Unlimited weight - On

Enemies HP - 1000% (Keeps the animal alive long enough for 4 to stick in)

Now i tried hunting, bears, Wisent, Boars etc and had no luck getting them to stick. The easiest animal by far, is your horse!

I used wooden spears and my own horse, in my village.

Save your game before attempting it, ensure you have an adequate supply of spears. Aim for around the saddle, either just in front or just behind. The impalement rate is far higher and the animal doesn't move or try to attack you.

I have posted a video for visual aid

As the description says 4 spears in an animal still alive.

I used wooden spears and I did this to a bear with no points in the hunting skill tree.

Setup
Customize a new game and have these settings to keep you alive:
Unlmited HP - On
Unlimited stamina - On
Lack or food and thirst - On
Unlimited weight - On

Enemies HP - 1000% (Keeps the bear alive long enough for 4 to stick in)

Bears location
There's a lake south of Gostovia (starting town) and east of Hornica, on the north eastern side of that lake has always spawned a bear for me.

Chop down trees to get logs, turn logs into spears with the crafting wheel go down to bears location and save your game before you attack the bear in case you run out of spears or the achievement doesn't unlock (some can be buggy). Right click pulls the spear back, left click throws the spear, eventually 4 will stick in.

I got myself 50 wooden spears just in case but I got the achievement within 30 throws