What is it about babies and their fascination with tasting everything? Are they hungry? Are they teething? Are they just weird?
Oral exploration is a key developmental stage. It allows babies to discover the taste and texture of different objects. Sucking reminds them of being in the womb and is one of the 5 womb sensations capable of triggering a baby's innate calming reflex. It lowers the heart rate, blood pressure and stress levels. After all, a baby's survival depends on sucking!
Until they are about 7 months old, babies can't really use their hands and fingers to explore objects. They can grip but don't have the agility to poke or prod with their fingers; but, they CAN control their lips and tongues, so will 'mouth' and 'gum' objects once they have the functional ability to put things into their mouths.
Babies mouths have more nerve endings per square millimetre than any other part of their body. Young babies move their fists, and whatever they may be holding, to their mouths and start exploring from there. This can continue until they are into their 2nd year; after that they can start to manipulate their fingers to explore most of the time.
Mouthing objects can also be a sign that their first tooth is about to erupt - this can occur at any time from 3 months upwards.
So, be hyper-vigilant about what you leave in reach of your baby but don't stress too much if everything goes into their mouths - they are developing and exploring in their own way.
When massaging your baby, choose an oil that is safe and organic because you can guarantee that whatever oil goes onto their hands will go into their mouths. In my classes I use organic jojoba; it is absorbed quickly, has no smell and no taste.