I wouldn't recommend trying this until you are at a high level (I did it around 20).
Go back to Velen or any place that has a pack of low level wolves. Remember how they gave you a hard time when you're level 1 or 2 (at least in the highest difficulty they do)? Well, now it's time to get your revenge. With only 1 or 2 swings you can easily take one down, very fast.
Alternative or complementary ways to get them to die quickly is to rely on the incineration effect of the igni sign and then kill the whole lot when at least some have their HP lowered or even using Venon bombs which continuously cause their HP to drop.
If this solution helps you in any way, please leave it a thumbs up to let me know. Thanks!