This technique suppresses the power of a cursed seal. Because applying cursed seals in the first place requires a great deal of skill, suppressing one with this technique also requires a great deal of skill. The preparations needed for this technique are quite arduous: users write several long lines of symbols in their own blood, which trail from the cursed seal through the surrounding area. Once this is completed and the technique is activated, the symbols converge towards and surround the cursed seal, the blood acting as a chain that prevents the cursed seal from spreading. Applying the Evil Sealing Method is quite painful, and recipients are likely to pass out after receiving it.
The Evil Sealing Method can only suppress cursed seals, not remove them. Its power also relies on the will of the recipient: if the recipient wants it to work, then it will fight off the cursed seal's effects as much as it can; but if the user would rather the cursed seal activated, the Evil Sealing Method will be powerless to prevent it. For this reason, after Kakashi Hatake suppresses Sasuke Uchiha's Cursed Seal of Heaven, Kakashi takes efforts to train Sasuke so that he won't be tempted by the cursed seal's power, notably teaching him the Chidori. This ends up not being enough for Sasuke and he willingly accepts the Cursed Seal of Heaven's influence. Over the following years, the Evil Sealing Method remains imprinted upon him, but inert since Sasuke has no need for it. When the cursed seal is ultimately removed, the Evil Sealing Method is removed as well.