You can hold your finger on the screen with the selection and then use another finger to go back to the Home Screen and open the desired app.
So a Mail to Things workflow would look like this;
- Hold your finger in the message (blank part of the header seems to work best for this)
- Wait till the drag and drop cue for item selection shows up
- Use a second finger to swipe up the Switcher bar (or swipe left for the last used app)
- Open your app of choice (Things in my case) and use the first finger to drag it there.
Here’s a quick demo:
EDIT: Works great for Safari URLs too. Yet another reason why that bar belongs to the bottom of Safari!
EDIT 2: Yoink users may find it far more useful on iPhone now.