The oldest Jonathan

You choose Jonathan first as he seemed quite reluctant. You are sure Jonathan will give you one of his testicles but you are not sure about Mark.

"Which one do you want me to pop sweetheart?" - You said sweetly

Left one, please - answered Jonathan

You grabs the testicle as hard as you can. It's quite small so it took you little time to pop it. After you dug your nails in and used both hands it took only a second. He seems in agony but he does not scream or cry. He is trying to act tough.