In a dimly lit room, a solo explorer, anonymous yet eager, stretches his limits. A chain, cold and unyielding, is his tool. He strokes his hard cock, lubing it with spit, then pushes the first link into his ass. The sensation is intense, a mix of pleasure and pain. He pushes more in, his body tensing, until the entire chain vanishes inside him. He jerks off, feeling the chain move with each thrust, then slowly pulls it out, his asshole widening, before collapsing in satisfaction.