Sorry I know this is not what you asked - believe me I have an app for everything - but when it comes to random pairs, I just count around the class: "One, two, three, orange, apple, pear, squirrel, bluebird, dolphin, one, two, three, orange, apple, pear, squirrel, bluebird, dolphin". Then I just say, "Okay, ones get together, squirrels get together...you get the idea." And they �re all in pairs! Of course if you use the same count each time, the friends might sit 10 people apart, but you can vary it.
Your mileage may vary clause
My example is for a class of 18 students. You have to change it if there are fewer or more students.You can also substitute narwhals for dolphins but they are harder to spell and their tusks can be dangerous in small classrooms.
Aren �t they awesome??