I can't believe you're not putting me on!!
There is a whole sticky thread devoted to 37D. But in case you are serious, the entrance to 37D is the first doorway on your left as you turn off Dundas onto the laneway. You will be greeted by the mamas as soon as you reach the first level above street level. Apparently there are also services offered on the next level, but I have never tried those.
I'm sure you are pulling my leg about your lack of knowledge on 37D, but maybe this info will help someone else.