Re: angel energy addictive?
In my experience, many angelics have fairly refined energy / high frequency energy.
Think of it like this - the raw "natural" energy you get from the world around you, the stuff most people naturally draw in and process, is unrefined. It's like wheat, or a complex carb. Most people, when they "digest" this raw unrefined energy, process it into a more refined energy, which they give off as prana. Prana, life-energy, is the refined, higher-frequency energy that living beings give off. Think of it like processed flour, simple carbohydrates.
Most people can get sustenance from the raw, unrefined energy, and can process it through their system just fine. (Some people, like myself, need that raw energy, and have the energetic equivalent of a sugar crash if they try to feed on prana; their systems need something to chew on.) Some people have some issues with their energetic digestive system, though, and it takes more energy for them to refine raw energy than the yield they get, so they're actually losing energy in trying to consume raw energy. These are vampires. (I also know vampires who can't process raw energy. When they try, they get violently ill, it hurts, they throw up, etc.)
Some people, like fae-kin and angelics (in my experience, anyway; YMMV), give off even more refined energy, like cotton candy, spun sugar. (I can't think of a better analogy more refined than "white flour", sorry!) Vampires often give off very refined energy too, since they process the prana they consume into an even more finely refined form.
So that might be why she finds your energy "tasty". It's very easy for her to digest, I bet.
"An' it harm none" is a ... limited understanding of Wiccan philosophy, but okay. We'll go with it. Point out to her that by not feeding, she is harming herself. If she feeds responsibly, she harms no one. Ambient feeds harm no one. Feeding from a willing donor does not harm them. In fact, some donors (such as myself) are actually healthier if fed on regularly, because of an excess of energy and a poor natural ground that results in energetic blockages (which results in lethargy and sluggishness and aches) if they don't expel the buildup of excess energy somehow (and often the easiest way is to expel it into someone else, or have someone else draw the excess off of you).