Where American bigwigs may come together for sex? (8)
I believe the answer is:
congress
I believe this clue is a double definition.
'where american bigwigs may come together' is the first definition.
(where US representatives meet)
'sex?' is the second definition.
(congress is a kind of sex)
'for' acts as a link.
(Other definitions for congress that I've seen before include "Law-making body of USA" , "National legislative assembly (as in the US)" , "US legislative body" , "Formal meeting" , "US Federal legislature" .)