Yes, this gets covered in basic mandatory reporting training. The issue with intoxication is generally the power asymmetry. If there is no asymmetry, there's less of a problem. It isn't a hard and fast rule though. If someone says or implies they don't want to fuck when sober, and you both get drunk and fuck, that's probably not great. Likewise, someone taking advantage of a body mass asymmetry to remain relatively more sober while consuming the same amount of alcohol is definitely still rape.

Basically, if only one person is drunk, there is a strong presumption of assault. If both people are drunk, there is no such presumption, and you'd generally defer to the nature of their relationship outsode of the drinking. So two complete strangers getting sloshed and fucking is typically safe. Two otherwise platonic friends doing the same thing is more of a grey area and you better be sure you are not misreading the situation. You getting drunk with a friend in the hopes they will make a poor decision they wouldn't make while sober is rape.