I work/socialise with a lot of Americans - so it is sometimes easier to adopt their terminology - though I refuse to use the term douche, that is just silly.
I was with an Australian and and Yank the other day and mentioned that I was going on a stag do in a couple of weeks. Blank looks all around. "A bachelor party" - recognition from the American, blank look from the Aussie. "A buck's party" - ah all got it now. Three nations divided by one language as they say. At least the Canadians say Stag, I believe