"出声地咂嘴" can be translated into English as "smack one's lips audibly" or simply "smack one's lips loudly".
Here, "smack one's lips" is a phrasal verb meaning to make a sucking noise with the lips, often as a sign of enjoyment or anticipation. Adding "audibly" or "loudly" emphasizes that the sound is clearly heard.
For example:
He smacked his lips audibly after tasting the delicious soup. （他尝了尝那美味的汤后，出声地咂了咂嘴。）