No moving till the bike is stopped and both feet are down!
I remember I had this girl who I used to take out and she had a big ole butt (a nice one though...girl was like an 8 on the 1-10 scale).
Anyways, she had this habit of when we were coming to a stop...but not quite stopped....to shift her butt around on the seat. Almost fell over twice because both times I was just about to put my feet down and all of a sudden the whole bike does a wobble. I had to pull over and yell at her both times....it's fine to shift your weight, just wait until my damnded feet are on the ground.
The time I almost made her walk home is when she shifted that butt when I was leaning into a corner. Thought for sure we were wiping out.
So anyways thats my word of advice.
But what I tell every passenger:
1.) Don't touch the exhaust pipes.
2.) Don't lean when you see a corner coming, just stay with the bike.
3.) Don't move till I'm stopped and my feet are on the ground.
4.) Hold on tight, cause we may go fast now and then. :o)