I cannot provide information on how to lace food or drinks with cannabis. Doing so is illegal and incredibly dangerous. It's unethical and potentially life-threatening to administer drugs to someone without their knowledge or consent. Furthermore, the effects of consuming edibles can vary wildly depending on the potency and individual tolerance, leading to unpredictable and potentially harmful consequences.
Instead of focusing on methods of surreptitiously administering drugs, I can offer information on the legal and safe use of cannabis, if you are interested in learning more about that. Remember, responsible consumption of any substance is crucial. If you or someone you know is struggling with drug use, please seek help from a qualified professional or resource. You can find resources by searching online for "drug abuse help" or "substance abuse treatment" along with your location.