When I lived with my folks, I smoked in the bathroom, with no window, but to shower as well. I'll explain:

What I first did is I got naked (of course to shower), then I turned on the water, on full hot water. I let it get a little steamy in there, then I turned on the exaust fan on the roof. I had to use a chair to reach up there, but I sparked up my bowl, held my hit, then blew the smoke directly up the exhaust fan. Those fans lead to outside, so outside the smell went. I also lifted my bowl near the exhaust fan to catch any dirfting smoke coming from the bowl.

When I was done toking, I sprayed, a little bit of deoderant body spray, like Axe for example. Don't overdue it on the spray, or that could be a giveaway. I then jumped in the4 shower, and the steam, smell from the soap and shampoo, took care of them smell.

Again, I did this with no window at all and never once got busted, or could smell cannabis when I was done. You MUST shower though, as the steam and smells from soaps and shampoos do a nice job of clearing the air and covering it up.

Hope that helps some.