There is no good way to short the Canadian residential housing market. Even if there were, the Canadian securities market is so illiquid that just the transactional risk in terms of bid/ask would make this trade ill-advised because you'll get raped when you want to reverse.
IF you are a homeowner with an incredibly bearish view of the market - sell and then take the proceeds and rent a place and wait for the drop. Or if you can try to find a buyer who will lease the house to you after the sale. If you don't already own a home - simply wait for an opportunity to buy.
The GTA has pockets that have not dropped and in some cases have held steady or even risen ver slightly. Anecdotally, I can use my own neighbourhood (Wanless Park area) as an example of a pocket that still sees a lot of demand. In fact, in April my neighbour sold his house for what is a record price for my block and it was by way of a bully-bid before the first Open House. I've seen more than a handful of houses come on market in the past month and all have had the same story - sold signs within days.
Note: I have no doubt that the days of rising prices are gone, and there is pressure to the downside. But with everything comes opportunity - even if you own a home that has declined. Eg: Even if your home has dropped in price - so have other homes. So if you wanted to upsize or even downsize - you can look for opportunities to do this with a smaller spread (if you are upsizing) or a bigger takeout (if you are downsizing). I'll be looking to downsize towards the fall - so looking for potential candidate neighbourhoods where I can start monitoring the takeout (or if I can find a decent sized home/condo I might even rent for a year or two).
But IF you are really, really bearish - then put your home up for sale, and bank/invest the proceeds and rent until the market reaches a point where you want to get back in. Just remember that houses are not a liquid asset and you pay for that lack of liquidity.