Good alcohol for flask without much liquor breath?

[Popinjay]

Kay, so I am going to start carrying a flask around to take swigs of during some of my easier classes. Now go easy on me cause I'm an alcohol noob of sorts, but what should I be filling my flask with?

As much as possible I would not like others to know that I am buzzed during these times. The biggest giveaway is liquor breath... so an alcohol that can somehow be minimal or mask on this would be preferable.

I'm thinking right now whiskey or maybe gin. Thoughts?