The "merging astral consciousness" meditation gets you familiar with sensing thought, emotions, energies, etc. Once you have mastered that you can manipulate those thoughts and energies. For example, there is a hypothetical person you hate. You can sense what thoughts are in their mind. Maybe they are thinking about next month's rent or what they are going to eat for lunch. You can replace those thought with thoughts of self-hate, suicide, cravings for hard drugs, and anything else you can think of that will ruin their life.
If there is someone you like, you can plant thoughts of you+love/lust into their mind while they are sleeping.