Tripping Staff
You can make a trip attack with your quarterstaff.
Prerequisite: Int 13, Combat Expertise, Improved Trip, Weapon Focus (quarterstaff), base attack bonus +6.
Benefit: You treat quarterstaves as if they had the trip special feature.
Special: If you are a magus with the staff magus archetype, you can use spellstrike on any trip combat maneuver you make with the staff.
Source: Ultimate Magic, p. 158