I assume you mean you've done all hypnosis stuff until final level? Goal for final stage of hypno stuff is to beat the sisters at same time whilst under the debuff from hypnosis, but it IS a tough fight, depending on your strength. Honestly, for first time run against sisters, its better if you haven't done hypnosis, because the debuff is a pain.
There arent really any techniques for beating it with debuff sadly, though if I remember correctly the advised level for it is about 40 and if possible to have nymph perk.