There has been a discussion recently about something called "gray rape," a contrivance proposed by author Laura Sessions Stepp that only serves to support men's excuses and explanations for sexually assaulting women. There have been good discussions about this at Feministing .
Any man who has sexual relations with a woman knows, deep in his heart, whether he has coerced her or not, whether she has consented or not, whether she has relented or not, whether he has pressured her or not, whether he has threatened her or not, whether he has assaulted her or not. Any man who says he was confused or not sure is prevaricating. There is no gray area about it.
Spend some time talking with men in court-ordered batterer intervention programs. Almost every one of them has sexually assaulted his female partner, under the influence or not. Being drunk is a disinhibitor, not an excuse or an explanation. Neither party is having "consensual" sex when he or she is drunk. But every batterer will tell you that they knew exactly what they were doing. The fact that they are batterers, of course, makes drunken sex just as non-consensual as sober sex.