derivation: U.S. Navy slang, probably archaic, from the days when combat ships had all-male crews. Refers to a male sailor who provides sexual services (manual, oral, or anal, as the passive participant only) to other male sailors while at sea on a long deployment due to the lack of female companionship. The "sea bitch" providing the services could be seen as either homosexual, or simply horny and driven by circumstances to his role. The recipient of his services would probably be seen as basically straight. See situational homosexualityand it's only queer if you're tied to the pier. Since the advent of females on most combat ships, this traditional role may have largely disappeared. (But see, the submarine service which does not accept females.)
"Dude, we've been on Westpac for four months, and I am so horny I'm going insane. There must be a sea bitch who could help me out."