LOL
it took me a moment to "get" this comic, but I understand now, amusing.
The way I done it was I drew a stick-man on the index finger of my right hand, another stick-man on the palm of my left and an inky smudge on the palm on my right.
Then I'd show someone the stickman on my finger, pretend to throw him in the air and catch him in my left hand (where he now appears) then I'd clap and go "woops" and show them the smudge.
yes, we were all children once!
---
Dad was flammable