The amount of alcohol depends on the temperature of the water and the air. At the beginning or the end of the season (late May to late September), or on rainy nights, a shot to tequila is sometimes required. Most Fridays its just optional.
One of my very favorite things in life is swimming at night in the bay. Its a truly transcendent experience where I feel like am part of the water and the sky, in a place I grew up on and have a strong connection to. Someday soon I will take the last dunk of 2015 and I will look forward to the first dunk of 2016 nearly every day.