So you’re almost correct. Taglocks are something that tie a working to a specific person, not just yourself. This could be as simple as a name and date of birth or as complex as physical parts of a person (nail clippings, hair, etc.). It works by giving the magic a direction, a target, if you will.
In my healing bag video, I used my fingerprint as a taglock that way if I couldn’t bring it with me during surgery, whoever carried it wouldn’t be affected by the specific spell and it would still target me.
You can see the video here 
HearthWitch did a great video on taglocks too!
