Here's a tip for a no-slip grip as you whip your stick:

The KIL Grip Tape is a roll of slightly sticky fabric tape that can enhance your grip by creating a tacky surface between your stick and your hand.  Many elite fighters use grip tape to help prevent disarms during intense training sessions.

KIL Grip Tape is 1-inch thick, and come in 30-foot rolls.  Choose your color: Black, White, Red, Blue, Neon Green, Neon Orange, Neon Yellow, or Gene LeBell Pink.