Officially you cannot remote mount the My Cloud. WD removed this option over a year ago when they introduced the OS 3 firmware for the single bay My Cloud units. Officially (and generally) the only way to remote access a My Cloud unit is to use; WD Desktop, MyCloud.com web portal, WD My Cloud apps for iOS/Android or the insecure FTP.
Unofficially if you have an older first generation v4.x single bay firmware My Cloud unit you could install the CloudDAVMod which allows for remote mapping of the My Cloud. NOte that this mod is NOT supported by WD and ONLY works on the older first generation v4.x single bay My Cloud firmware.
http://community.wd.com/t/app-clouddavmod-various-versions-for-firmware-v4-09-2016/161543
