Spin Jump is a out of battle move in the Mario and Luigi series.
History
Mario & Luigi: Superstar Saga
The Mario Bros. first use Spin Jump in Mario and Luigi: Superstar Saga. To use it, Mario must jump on Luigi, allowing the bros to spin and fly in the air. The player needs to learn this move to unlock Splash Bros. To learn it, the Mario Bros. must find the Stardust Bros in Stardust Fields.
Mario & Luigi: Partners in Time
The Mario Bros use Spin Jump once again in Mario and Luigi: Partners in Time. In this game it is taught to them by Toadsworth and Toadsworth the Younger before the heroes travel to Yoshi's Island. However, the move itself remains unchanged aside from the order of the Mario Bros., with Luigi being on top of Mario.