There are several ways to use or apply agarwood oil. A dab on my shirt sleeve is one of my favourite. To me, Agarwood (Oud) Oil is very personal as it could upset some people if they have not tried it before, and to be on the safe side, a small dab is enough for me as it would last for a day if not two.
I have a habit of touching my chin when thinking or focusing on something, Since, the oud oil is on my sleeve, this will be a chain of action
oil on shirt sleeve -> thinking- > moving hand touching my chin -> Smell the oil -> Calm, and clear mind.