To dream that you are drinking alcohol suggests that you are seeking either pleasure or escape.
If you dream of drinking alcohol in excess, however, this signifies feelings of insecurity and regrets. You worry that people will discover who you really are.
If you dream of hiding your drinking from someone, especially from a parent, it means you have been keeping a secret that is going to end up hurting you if you don’t let it out.
Also see “Hangover”