What I don't see discussed already here is that it depends on the relationship. Both of you being drunk is not the right time to decide for the first time that you want to do it, but if you've already made that decision and now happen to be drunk, whatever.
Consent and being drunk is not about a power imbalance, or at least not completely. It is about both parties' capabilities to consider the consequences of their actions. Will one or both regret what they've done later? How would they tell, if they were either of them drunk?