Taunt application was expanded in DMC3 featuring more intelligent use during the run. This is based on the player's good judgement. The DT increase varies by how high your style is and How many enemies are around, it's possible to get as high as 6-7 symbols with only 1 taunt.
Taunt is commonly used when huge group of enemies are killed with DTE followed-up by a roll. Vergil can expand this further with his Yam Taunt “You shall die!”. Meaning, when there are enemies present and Vergil remains in the pose, he will start rapidly gaining DT gauge.
Basic taunt usage with Vergil. This can also apply with Dante minus the Yam special