Instantly if you ingest it or have it on you. Ingesting it is just safer because then a vampire can't smell it, and they'd have to bleed it out of you or wait for it to leave your system.

[Unlike wearing it where the second someone tears off your necklace or refuses to give it back, you're 110% able to be compelled. Her gaze dips down to her lap for just a brief second at the memories.]

I won't try to compel anything weird or dangerous. I don't think I could even if I wanted to.

[You know, seeing as how this would be the baby vampire's first time.]