How euphemistic is 傢伙?
I don't know the nuance carried the English word "tool". But according to your description, I don't think there's such nuance in Wang's article. It is just a normal euphemism, with no added meaning to the original word (penis).

Basically, 傢伙 would carry a similar connotation as "manhood" or "member" (maybe without the informality associated with "member").