Chasing a toddler around is exhausting. The last thing you need is to get into a wrestling match with a poopy diaper and a flailing child. Here are some tricks to try (that also work with wriggly babies, 5 or 6 months and older, too):
Give a warning: When the stink-bomb hits, let your toddler know that he'll be getting cleaned up in a few minutes. Advance warnings help with transitions.
Time it right: Don't interrupt your toddler's flow of play if you can help it. Deal with the stinky diaper when there's a pause in the action.
Have a special basket of "Diaper Changing Only" toys that are normally forbidden: We have an old remote (with the batteries removed), a broken watch, a semi-functioning bright orange solar calculator, and various interesting items that normally wouldn't be allowed (like small cardboard boxes and other unusual things). Of course, safety is the number one concern. But since you're right there for those few minutes, you can monitor. When you're done, the toy goes back into the basket for the next diaper change.
As with all Toddler Power and Control Issues, parents need to assume -- and exude -- a calm sense of flexible authority. You're in control: Don't beg or plead for cooperation -- quietly assume you'll get it (and more often, you will).
Dr. Heather The BabyShrink