How to translate?

[dsank0]

His reply had been a manly knuckling of his forehead.

 

[MikeNewYork]

His reply had been a manly knuckling of his forehead.

It appears that someone's knuckles hit someone's forehead, but it is not clear as to who or why.

 

[dsank0]

It appears that someone's knuckles hit someone's forehead, but it is not clear as to who or why.

There's more:
"Carlo, handsomely sunburned, blond hair neatly cut and combed, sipped at his glass of homemade wine and said, "Nobody can tell Mike what to do." Carlo had become a different man since moving into the mall. He knew his place in the Family and kept to it.
There was something that Kay didn't understand in all this, something that didn't quite meet the eye. As a woman she could see that Connie was deliberately charming her father, though it was beautifully done and even sincere. Yet it was not spontaneous. Carlo's reply had been a manly knuckling of his forehead. Michael had absolutely ignored everything."

 

[MikeNewYork]

There's more:
"Carlo, handsomely sunburned, blond hair neatly cut and combed, sipped at his glass of homemade wine and said, "Nobody can tell Mike what to do." Carlo had become a different man since moving into the mall. He knew his place in the Family and kept to it.
There was something that Kay didn't understand in all this, something that didn't quite meet the eye. As a woman she could see that Connie was deliberately charming her father, though it was beautifully done and even sincere. Yet it was not spontaneous. Carlo's reply had been a manly knuckling of his forehead. Michael had absolutely ignored everything."

I appreciate the extra context, but it didn't help me.

 

[dsank0]

I appreciate the extra context, but it didn't help me.

Thank you, anyway