When flavor goes in

A one-step page because the step is one decision and getting it wrong costs the whole batch's character.

Last, and off the heat

Melt fully, take the pot off the heat, let it fall towards pour temperature, then add flavor.

Anything volatile added at full melt temperature partly leaves into the room. The smell of the workshop is the flavor you are not selling.

Color, by contrast, can go in earlier because pigment is not volatile, and it often benefits from longer dispersion.

How much

By weight, as a percentage of the batch, from the supplier's recommended range for lip use.

Start at the bottom of the range. Flavor reads stronger at the bench than it does a week later in a capped tube, but it also reads harsh above a certain level in a way that does not soften.

If it is faint after a week, the answer is more often sweetener or a cooler addition temperature than a higher dose.

Stir, do not whip

Fold it through gently. Beating air into a cooling melt gives you bubbles in the tube and a larger surface for oxidation.

Ten seconds of careful stirring is enough in a liquid this thin.

Then pour

Immediately. Every minute between adding flavor and filling is loss.

Which is the argument for having tubes racked, labels ready and the bench clear before the melt goes on the heat at all.

References