Consent. It's a huge part of sex, but what if alcohol is involved? How much alcohol is needed for it to no longer be conscientious sex? When does it become rape?
Alcohol is considered an aphrodisiac. That means alcohol stimulates sexual desire. While it may make you hornier if you have too much, you will not be able to have good judgment on your sexual partner or safety. Alcohol is great to get the mood going. You are calmer, hornier, and more open to new things. Personally I believe you should talk to your partner or date prior to drinking so you have boundaries set in place. That way, "Do whatever you want with me" won't turn into "He took advantage of me being drunk." Also remember that just because they consented prior to having sex doesn't mean that they can't back out. It's never too late to back out. Stand up for yourself and say "NO," "stop" or even "I no longer want to do this." Having sex while under the influence is a very gray area and should not be taken lightly.
Now what if you are in a party and don't know the other person? Can they consent? I believe if you are tipsy, as in you feel good, can fully function and think clearly, then yes you can consent. They have to be able to walk on their own without stumbling and make sense when they talk. If they are slurring their words then they are drunk. Use your best judgment.
If the person is drunk, they cannot consent. Most likely he or she cannot think clearly and will have no recollection of what happened, and if they do they might just end up regretting it and at that point it might even be considered rape. Just because they are all over you and begging you to do them does not mean that they are fully capable of consenting. If the person is passed out they cannot consent. I repeat, they cannot consent. I don't even think this one has to be explained. This is rape. Only if your partner specifically said "I want to get so drunk that I pass out and then I want you to have sex with me" is it okay.
As fun as alcohol can make things, it can also make them go horribly wrong. If you have too much alcohol, you might feel numb and some guys have confessed that they can't get hard when heavily intoxicated. Sometimes when you are drunk you may say or do things that are unsafe and that you might not normally say such as "Let's not wear a condom" or "cum inside of me." Heavy alcohol can also cause unwanted pregnancies and if you are with someone you don't know you may even get an STI.
If you are in this situation and aren't sure if they are able to consent, then maybe you should just walk away from it. It's sometimes better to wait till they are sober than to do something that can potentially ruin your life.