Personally, I avoid drinks that will raise my levels. Beer is, unfortunately, out of the equation. Red wines, dry white wines and spirits are fine. If I'm below 6 on a night out, I'll have a beer as it will raise my levels, but that is the only time I drink it.
I don't experience a sudden drop because of alcohol, it's a gradual thing. You may be different though. I find alcohol will affect my levels if I've had more than 2 glasses of wine. I would only give a correction dose if I was in double figures and then I'd be cautious - I don't want a hypo on a night out. When I drank beer, I wouldn't need a carby snack before bed because the highs from the beer would be enough to counteract the fall I'd get.
When I'm out, I test myself every hour, mostly in the vein hope that my levels are suitable for a beer, but it's important to be diligent with your diabetes management if on a night out. Also, don't forget to take your long acting out with you and inject at your usual time.