"I need to know if there's a variation on the obfirmo solution that can be made non-toxic, and brewed into a liquid form with pigmentation." William hesitated, not wanting to say too much, before adding, "Ink."
It was entirely possible that Nate would ask and Gabe would laugh in his face. That or he'd immediately devote hours better spent sleeping to exploring every possible way such a thing might theoretically be done, until someone finally rubbed the smudge of ink off his nose, picked the pink peep-canary feathers out of his hair and sent him away to bed.
What would most likely not happen would be Gabe appearing when William least expected him at an odd hour of the afternoon, draping himself over William's desk and demanding with a salacious grin why William wanted to know. William swallowed and tried very hard not to care. "There's also the tutaminis tincture, but the potion would need to be injected under the skin, and tutaminis would prove lethal in its common finished form. There might be something else as effective, I don't know."
It would have been easier to tell Gabe this directly and receive thoughtful nodding and a spew of information Gabe knew offhand that William wouldn't have been able to find in all the books in the Hogwarts library, but...well. William's grandfather had a saying about wishes and unicorns. He knew better than to pursue vain hopes.