Humor - I love interruptions that help get things done. Humor is
one of those.

Ever heard of twins digging in their heels about anything? Using
the potty, going to dinner, stopping playing, going to nap or bed?
Humor can be the lever and fulcrum to get things moving.

You have the unique opportunity with twins to use humor with one to
get both in the direction you want to go. They are so tuned to each
other that they want to share in the fun and laughs. They tend to
be so synced up that one doesn't want to be left behind. So try a
joke, a tickle or a funny face or sound and observe the result.