have a few
To have multiple alcoholic drinks, especially to the point of becoming mildly intoxicated. John's usually quite reticent around other people, but he becomes the life of the party after he's had a few. Nothing helps me unwind after a long week of working like having a few with some good friends.
have a few
drink enough alcohol to be slightly drunk. informal 1991 James Kelman Events in Yer Life In fact it's hard to talk politics at all down there. I tend to keep my mouth shut. Unless I've had a few.
have had a few (too many)
(informal) have drunk a lot of alcohol: Look, he’s had a few and he really shouldn’t drive home.You’ve had a few too many, Paul. You don’t know what you’re saying.