Feinting is a
standard action. To feint, make a
Bluff check opposed by a
Sense Motive check by your target. The target may add his base
attack bonus to this
Sense Motive check. If your
Bluff check result exceeds your target's
Sense Motive check result, the next melee attack you make against the target does not allow him to use his Dexterity bonus to AC (if any). This attack must be made on or before your next turn.
When feinting in this way against a nonhumanoid you take a -4 penalty. Against a creature of animal Intelligence (1 or 2), you take a -8 penalty. Against a nonintelligent creature, it's impossible.