"I wish my family wouldn't mind all this." Matt said, negating any concerns about Mr. Laird interfering.
That, on the other hand, seemed to take a lot out of the wand. The silver rod actually seemed to vibrate differently and glow in a few spots, depicting a number of points evocative of some spiritual structure, before returning to normal.
Still receiving a blowjob from Brett, Matt experienced the troubling sensation of 'low battery' from the extremely expensive action of 'fighting all of his dad's secret magic defensive measures and winning'. The wand accumulated more magic over time to get out of paying for the little things, but it'd take a while to do too much big stuff again. Of course, if it came with charging instructions...
Matt focused on the wand and concernedly said "I wish I knew how to charge the wand battery," receiving a fairly simple sensation of 'pay a price' in response. The nuances of this were clear: take from other magic reserves, use some of the principles in the wand, or pay from the march of time and just wait (perhaps a few minutes to make some small alteration).
The principle of exchanging matter and energy was the simplest answer, draining things from the world: by 'vanishing' things (or shrinking down same-typed inorganic matter as opposed to complex things like people and their bodies), one could get more energy for the wand without having to wait.
The principle of exchanging attributes was much more fetishistic. Drain vitality and attributes from others in order to have reserves of those attributes to give out instead of making them whole-cloth from magic. There were limits to this and it would start costing again if that meant shrinking or growing things beyond humanly plausible ranges (since magic would have to be imposed to make it work in contravention of physics), but it did give a few interesting opportunities to shrink and grow people just by siphoning away unwanted things like excess fat.
There was another principle about creating art or something and cheesing in new energy by creating immaterial concepts in excess of the physical circumstances needed to feel them, but that was all complex magic stuff that wasn't well-explained beyond 'yeah that charges the wand'.
'Take from other magic reserves' was...an interesting option. Matt's dad apparently did something to himself that was weirdly expensive. Maybe if Matt controlled him instead of making him just not mind what was going on, there'd be some interesting advantages there.
Even though Brett's blowjob technique was average and his huge dick giving plenty of space in the teen's mouth, Matt came quickly. Brett swallowed and looked up at Matt expectantly, clearly desiring more (and his oversize cock certainly ready for it).
This was certainly a decision point alright. Matt couldn't afford to take things too quickly, but taking time was on his side. It'd be some time before Brett would be missed at all, and longer for Matt because he'd kept his family from abstractly objecting. Corrupting the DeSoto family was a medium-term goal, one that Matt might have to spread over several wishes now that he'd wasted however much time that wand had spent sealed away.