I would just like to point out that carrying small of back is one of the most dangerous positions to carry. Not only is it very visible and easy for others to access when sitting, but if you are pushed down in a struggle/fight the gun can crush your lower vertebra and paralyze you. This isn't one of those internet rumors, many police officers and civilians alike have fallen victim to this type of injury. If it works for you, by all means do what works, but do be warned that it comes with a huge risk. Offsetting the gun to the right/left as tomservo92 said will give you a better shot at surviving a push/fall while giving you quick access to your firearm and decent concealability. Just some food for thought.