Pour Tequila, Vodka, Margarita mix (I use "Jose Cuervo - Margarita Mix", but u can make your own from triple sec and lime juice), squeeze lime wedge and add bitters into a shaker.
Strain into a high ball glass over ice. Dash in the pinapple (about 25-50ml) stir and serve.
... sounds a pain but i liked it, so did the customers!!