Instead of a gag, I used a rubber cock and gagged the slave's mouth with it. I picked up a branch from the ground and whipped him with it. The slave sat with his bare ass on the sharp bumps, and when I started to stomp on him, the bumps cut into his bare ass, which made him scream and beg for mercy. Then I pissed on him and he had to go home smelling of my piss.
(after the shooting, the slave collected all the garbage in a bag and threw it in the trash on the way home)