How to politely tell the bartender....

[Warik]

.... that she's watering your drinks down and you kindly request that she discontinue doing so?

I swear. I'm out drinking with my buddy the other night and we're asking for tequila shots in between our beers and the beer was packing more of a punch. There's NO way those shot glasses contained only tequila. We even tried switching brands and it was still the same crap.

I decided not to tell her "hey fatty, stop watering down my [censored]!" for fear of her using the solid black color of my next "Perfect Pint" of Guinness as camouflauge for a big glob of spit.

What's my play?