A very different drink

I came across a new drink last night that I'm just not sure about at the moment. I tried a bit and it just left me confused. Apparently it's not unique to Abu Dhabi (or the UAE) as it's name would suggest. The drink was a Fosters Mexican, but I guess it could just as well be a Heineken Mexican, a Carling Mexican or even a Stella Mexican! You get the idea. I tried to guess what this drink could be, but just couldn't! I mean, who would dare mess with the sacred pint of lager and start adding things to it? I have a pal back in Birmingham who drinks a lager top, and that I can just about accept as it adds a little touch of sweetness to a cold pint. So what is it? Three simple ingredients, two of which are usual accompaniments of the most popular Mexican drink, tequila. Take a pint glass, absolutely coat the rim with salt, poor in the bottom a very healthy measure of freshly squeezed, pure lemon juice then fill up with a draught lager of your choice. A very strange combination, which the barman at 3rd Avenue assures me helps you not get drunk! And who am I to argue with the font of all knowledge that is a barman! Was half expecting him to tell me that it also contributes to my 5 a day!