Obviously you can add drops of essential oils to the surface of a Subitism heater... This is a great way to add a little kick to a blend. I found sandalwood oil performs particularly well in this context. I place a drop of oil on the wood splinters and the scent is nicely boosted. Just putting a drop of oil on the burner and observing its aroma when heated rapidly gives you a very different perspective, especially in terms of the base note of the oil. This is also an easy way to detect the presence of fixed oils that may have been added as they produce a classic smoky oil scent when heated. My sandalwood oils always produce an excellent aroma across all stages of evaporation when he dabbed on the Subitism. Wish I could say the same for the agarwood oils in my stash. They perform in a puzzling and inconsistent manner when heated this way. However I Just put a dab of one of feel oud’s bio thai oils on the burner with a very pleasant effect.