San Pedro (Echinopsis pachanoi) is the sacred cactus from Ecuador and Peru. This is a cutting, which you can grow larger. Once it has taken root, it will grow very fast. In fact it's one of the fastest growing cacti in the world.
Plant the cutting on the surface of topsoil mixed with sand and perlite. Keep the cutting in the shade or indirect sunlight and water regularly. After about half a year the cactus will have formed roots and the cutting can be repotted in the same soil mixture.