For easy wyvern milk you can take a turret boat into the wyvern cave near crystal cave by SW area (assuming you are on ragnarok) & set the turrets to kill the alpha wyvern. This will give you 50 wyvern milk. You will need 6 turrets with at least 100 bullets in each to do this.

Or

Go into the same cave with a boat or raft,agro a wyvern onto you by shooting it,then take your raft or boat to the entrance & put it half way out. This causes the wyvern to become stuck & you can tranquillise it. Make sure it is a female & be careful,as the torpor on these beasts are nearly the same if not faster than a giga drops.

More Wyvern Taming & KO Tips