Soft wet lump in mouth (3)
I believe the answer is:
gob
This could be a double definition.
'soft wet lump' is the first definition.
'gob' can be an answer for 'lump' (I've seen this in another clue). I am unsure of the 'soft wet' bit.
'mouth' is the second definition.
(informal term for the mouth)
'in' acts as a link.
Can you help me to learn more?
(Other definitions for gob that I've seen before include "Clot of a slimy substance found in bog" , "A slangy mouth" , "Mouth (slang)" .)