Like other members of the Euphorbia family (poinsettia, crown of thorns), pencil cactus exudes a milky latex sap that can be irritating to skin and toxic if consumed. This succulent tolerates a wide range of light conditions, but is happiest in full sun or very bright indirect light. Soil should be allowed to dry out in between waterings. Water when the soil feels dry down to your first knuckle. NOTE: If you come in skin contact with the sap be sure to wash it off with soap and water as soon as possible as it can cause a pretty nasty burn on some people. Likewise if you get it in your mouth or eyes seek immediate medical attention. If cutting or pruning the plant be sure to wear long sleeves, gloves, and eye protection.