we did that on skis before I started wakeboarding and when we were bored with the planks. One would start on 2, the other on 1, step off onto the back of the other skis once up. We did that a total of twice and even went for a while sharing one ski after a statement that went something like this (I was standing on the back at the time)
other: "Hey, you know that right ski?"
other: "it's gotta go"
Before he got "it's gotta go" out, I felt it fall off and go behind us. That was fun for the 10 seconds we stayed up after that.