Power Tapping (Aura) from Rory Fansler's Supernatural Energy in Pyramid 4/1 (pg 36)

[Plane]

This specialty of the PT skill refers to a "specific kind of being" and notes "such as mages or spirits" as examples, though I'm not sure if it's meant to mean all mages/spirits or some of them.

I would assume that when this can target an Energy Reserve that it only refers to ER (magic), though it doesn't say that so maybe it lets mages draw energy from ER (psi) and similar?

I'm wondering that if this doesn't apply to anyone with ER (magic) if perhaps there is some kind of special version of ER that it could apply to.

The idea of an ER you can loan others' access to was actually in pyramid 3/1's "Improved Zombie" which introduced the idea of adding Affects Others to it like you would with movement abilities.

In the example it has the zombie use a Ready maneuver to give the mage access which is how Powers defined that enhancement as working for other advantages... there's no mention of the mage needing to take a maneuver though.

So it seems like Power Tapping would work differently since it's the tapper (mage) who explicitly takes the maneuver instead while it only mentions consent of the tapped but not maneuver choice.

Could we just assume that "swap who uses the maneuver" is a 0pt feature, kind of similar to how a couple Healing versions in Power swap it from the healer making the attribute roll to the healed making it instead?

[Refplace]

Power Tapping was meant to work for whatever source is appropriate in the campaign and fits the user. A psychic vampire could tap emotions, a fire elemental tap fire, etc. Word count forced me to trim some of the original material that would have made that clearer but I was really grateful to get all that I was able to in there.

Mages and spirits are typically different kinds of beings, though that depends on the setting.
You can only tap and transfer energy from and to a similar Energy Reserve so magic to magic or psi to psi.

Good callout on Improved Zombie, I had forgotten about them. However I arrived at the idea the same way, using the Affects Others modifier from GURPS Powers and would treat it that way. As it clearly states you need to use a Ready maneuver I felt no need to repeat that. Specific cases could vary but typically an apprentice or mage with that ability (ER with Affects Others) would take a Ready or optionally Concentrate to sort of chuck the energy to the receiving mage. However Power Tapping is an action taken by the mage who is drawing or pulling on the energy. In this case the subject would not need Affects Others on their ER.

I hope this answers your question and thank you for asking it and reading my article!