When you are turned on by drunk girls or when you think drunk sex would be a lot looser or a lot more of a turn on than if you are sober, then read what is going on in your body when you have drunk some alcohol.
The gift it gives you lies within the effect that it suppresses all your inhibitions, so you are a lot more willing to do things you have previously hesitated about. Still, if you have fiercely opposed against something, this is not going to make you change your mind.
Its other effect is that it does not only loosen your morals, but also your muscles. This is why anal sex is a lot easier drunk, since those muscles need to relax, as well. But on the other hand, this is the very effect that makes it hard for men to reach orgasm – in case of an excessive amount, even erection becomes a challenge – while women cannot provide enough lubrication for their own vagina, but their orgasms may become less intense, as well.
What you should keep in mind, though, in case of the first time you get drunk with a partner is whether you know what you can expect as its effect on your morals. If you have drunk with friends before and it made you aggressive, then you are likely to hurt the person you want to have sex with, so you should at least limit the amount of alcohol that you consume.