Is throwing watermelon rinds a Sunnah, and if it has only been reported from the Companions, does that fall under the Sunnah of the Prophet, peace be upon him, which he commanded to follow?

The Companions of the Prophet (peace be upon him) used to playfully throw watermelon rinds at each other, and this was a form of permissible jesting. Jesting is permissible and lawful as long as it is free from prohibitions. It has been authentically reported that the Prophet (peace be upon him) used to jest, and he would only speak the truth. Jesting is a Sunnah for those who do it well and in its proper place. The righteous predecessors used to entertain themselves with some permissible jesting to help them endure in truth. Throwing watermelon rinds, specifically, is not a Sunnah to be emulated. Rather, what is required is to emulate the Companions in their magnanimity, humility, and fostering affection among people through lawful jesting.