The slapper was on offense, and attempted to bring his hands over to slap the backsides of his opponent's hands. This must be done with sufficient speed, because the slappee's goal was to pull their hands away, and out of the area where the hands overlap, to avoid the slap. If the slapper missed the hands of the slappee during the slap, then the roles must switch.
Webnovel 
We always called it hot hands lol
The slapper was on offense, and attempted to bring his hands over to slap the backsides of his opponent's hands. This must be done with sufficient speed, because the slappee's goal was to pull their hands away, and out of the area where the hands overlap, to avoid the slap. If the slapper missed the hands of the slappee during the slap, then the roles must switch.
Super Gene
Sci-fi · Twelve-Winged Dark Seraphim