I use my fingers too :lol:
If I smelled my circuit for hours, then I feel that I have turned into a dog! :lol: :shock:
But smelling is ineffective, until you see smoke! and trust me, the smell is not good. So go spray some air freshner on your circuit, and maybe the smoke will push up the air freshner smell. :lol:
BUT, if your circuit is precious, ignore putting air freshner on it.
It is better to use your finger, because it detects heat before the smoke arrives. In fact, my finger prevented parts from smoking, because when my finger starts to get hot, I immediately disconnect the power.