Pipimi is referencing glitches that cause a 3D character model to reset to its original binding pose (which is commonly a straight, arms out T pose like you see here.) I'm not sure if there's any one game in particular being parodied in this instance, but a quick googling suggests SSB4 as one of the more prolific examples of this.
I can do it too ~ ♡Oh my ♡ That's so cute! It's like a buggy 3D game.Oooooh myyyyyy.... What a perfect model walk...This is a special way to walk without dropping my grandfather's ashes.s....s...Sliiiiiiiiide-