Yes? Tell me more!
There are two sets of twins I remember most fondly.
One was a set of twin boys, age 10, whose father was a professor who wanted them tutored to prepare them for college level English (at age 10!!). They were bright, engaging, generally lots of fun to with, but full of the games identical twins love to play on those who can't tell them apart.
My other favorites were two college level girls I taught for two semesters in sequential courses--both had been plagued by learning disabilities in their elementary and junior/senior high school years but had refused being placed in special education, deciding instead that sheer determination could overcome their challenges. Normally, that's not a path I would have recommended, but these girls were both brilliant and determined beyond anything I'd ever seen. Like the boys, they were identical, but no "fool the teacher" games from them! One went on to become a lawyer, the other a businesswoman with an MBA. I think it's been almost 20 years since I taught them, and they remain among my very favorite students of all time.
Since I worked with older kids, I don't have any experiences to relate with little ones, and I'm sure that's the stage you're most interested in right now--like how can we be sure which one we just fed so we don't feed him/her twice? With puppies, we use different colored collars--green boy, yellow boy, teal girl, etc. You might want to try that!