When the product page of the particular item you want says "sold out", you will see an "Out of stock - notify me!" box where you can enter your email address. Enter your email, click the email me tab, and tadaaa, your email is stored.
This nifty app really works well. As soon as the item is back in stock, you will be the first to know. Our inventory team frequently restocks our bestsellers. That being said, other products may take longer - especially if we're bringing them in from overseas (this could take anywhere from six to eight weeks). So patience is a virtue. However, if you'd like to enquire about exactly how long an item will take, please feel free to drop us a line. We can also advise on great alternatives if you can't wait a single day for some sexy fun.