How to right-drag using trackpad only, for Windows on MacBook

You can do this on the Macbook Pro trackpad by pressing down with two fingers hard enough to engage the mechanical "mouse" button built in to the trackpad. Drag your item(s) to the desired destination and then release the pressure off the button and... voila! Windows will display the right drag menu at that point.

Unfortunately this doesn't allow "locked drags" where you can continue dragging long distances by picking your fingers up off the trackpad surface and quickly repositioning them to continue the drag.

Since right-click in Mac OS X trackpad is done through two-fingers clicking, what you're asking is pretty non-Macish. On OS X, if you two-fingers click and drag, only the first two-fingers click is perceived by the OS, which pops up the option menu instantaneously.

There seem to be nothing also in VirtualBox preferences. VirtualBox (as well as other similar software - Parallels) treat the trackpad in an OS X way: for example, in a virtualized Linux I scroll down a page using the classic Mac two-fingers scroll; this is done in order to standardize the behavior of your trackpad.

If you're fond of Windows, give a chance to Bootcamp and see if in a native environment you can find a proper solution.

Try touching 3 fingers down, keep one down, let up the second, and drag with the third.