There are times that I drink a lot with my friends.So I can give you what it does to me but my doctor always tell that alcohol can create very different effects on different individual diabetes.
My advice is that you should start moderately , like a 33cl beer or a glass of wine and try to link them with coke , 7up or something.
-Beer:Increases b.s. in the short run but decreases suddenly after a while . If you feel nauseous without drinking a lot , check your blood sugar.Because you may end up vomiting.Low blood sugar with alcohol is not good , never forget that.
-Wine,whiskey:Increase in the short but not in a similar way to regular drinks.I don't remember it making sudden drops .
-Vodka:Also does sudden drops in b.s similar to beer but not as crucial as the beer.
Try not to drink cocktails until you get a knowledge about their ingredient.
Also knowing the main ingredient of the alcohol is important , like wine-grape , beer-barley , vodka-potato or rye , rum -candy cane and goes on.Briefly they are all coming from carb.family but they act different when distilled into alcohol.Those sudden drops are occuring because of that.
Another thing is that , alcohol drinks doesn't directly increase my blood sugar similar to a regular soft drink.A 7up gives around 100 increment but alcohol generally has a lower increment forsame litres of consumption.
Always keep that in mind , these happen in my case ,as it is your first time , it is important to understand how it effects your blood sugar , you can think of it as an experiment.Adjust the input and observe the output.