According to Richard Feynman in his book “Surely You’re Joking, Mr. Feynman”, this was indeed something people did as a prank.
I didn’t mention the “Demon” core incidents and I did specify Slotin was demonstrating the process to people and bypassed the safety precautions.
“Tickling The Dragon” was the “prank” I was referring to, but Slotkin was doing the equivalent of “tickling the dragon” by bypassing the safety procedures, even if he wasn’t doing it as a prank.
Well OK, if you say so.