The actual Gun Gun Pixies is on the smaller screen for most of the video’s run time, but you can delight in Ōtsubo and Imamura’s reactions below.
The entire concept of Compile Heart’s Gun Gun Pixies—which has tiny aliens sneaking around an all-girls dorm to observe human interaction and learn how to help their planet’s own relationship issues—is basically an excuse to watch girls stretch in their underwear.