Thanks for your question, my name isXXXXX and hopefully I can be of some assistance.
I would hazard a guess that he probably sniffs/licks those areas most since they are the likely places for a woman to wear makeup and/or fragrant lip gloss, perfume, ect. He is probably smelling these products on your skin and then trying to lick them because they smell sweet.
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By your previous description it sounded like your cat was exhibiting this behavior all the time. With your additional comments I believe that he is likely trying to rouse you from your sleep for attention or food. This is a sign of affection on his part, and cats frequently groom one another as well. In terms of an infectious risk to you, cats do have bacteria in their mouths, but unless he is breaking your skin, it should not lead to any infection.
I hope this additional information was helpful.
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