He talks constantly and puts pressure on snake (8)
I believe the answer is:
prattler
'he talks constantly and' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'pressure on snake' is the wordplay.
'pressure on' becomes 'p' (abbreviation. I am not sure about the 'on' bit.).
'snake' becomes 'rattler' (rattler is a kind of snake).
'p'+'rattler'='PRATTLER'
'puts' is the link.
Can you help me to learn more?
(Other definitions for prattler that I've seen before include "source of gossip" , "One talks" , "One going on" , "One talking foolishly" , "One may go on" .)