I've got a Throttle Rocker around here somewhere. I accidentally knocked it off my DL1000's grip while slowing for an exit once.
Rode about 4 miles exit to exit to get back to the point it happened. Luckily, it was still in the emergency lane unharmed. =)
On a long trip and in a pinch, you can make a similar device out of a heavy rubber band and some popsicle sticks.
Looks weird, but works and you get to eat a popsicle or two!