Hover( Monster Manual II, p. 18)
The creature can halt its forward motion while flying, regardless of its maneuverability.
While hovering, the creature can attack with all its natural weapons, except for wing attacks. Some creatures may be able to make additional attacks while hovering, as noted in the creatures descriptive text. If the creature has a breath weapon, it can use the breath weapon instead of making physical attacks.
If a creature hovers close to the ground in an area with lots of loose debris, the draft from its wings creates a hemispherical cloud with a radius specified in the creatures descriptive text. The winds so generated can snuff torches, small campfires, exposed lanterns, and other small, open flames of nonmagical origin. The cloud obscures vision, and creatures caught within it are blinded while inside and for 1 round after emerging. Each creature caught in the cloud must succeed at a Concentration check (DC 10 + 1/2 creature's HD) to cast a spell.
A creature without this feat cannot halt its forward motion without falling. A creature with average, poor, or clumsy maneuverability can slow it's flying movement to only half of it's fly speed. (See Tactical Aerial Movement in Chapter 3 of the Dungeon Master's Guide.)