Choose a recognisable idea
A tag can be a spoken phrase, a sung fragment or a short sound design motif. The key is recognisability, not complexity.
Record several deliveries of a short phrase and choose the one that remains clear when played quietly over a busy beat.
Record clean source audio
Use a quiet room, consistent microphone distance and a few different performances. Clean source material gives you more options during processing.
Capture a dry version before adding pitch, distortion or reverb so the tag can be adapted to different productions.
Process for character, not novelty
Pitch shifting, filtering and delay can create identity, but too many effects can obscure the words. Keep the main phrase intelligible.
Compare a dry take, a lightly processed take and an extreme effect chain at the same playback level.
Place it with intention
The tag should identify the producer without interrupting the artist or masking a key musical moment.
Test it in the intro and at a transition, then check that it does not cover the first vocal line or a defining melody.