So my lovely gf bought me a galco concealed carry paddle holster for my birthday. I really like it, but I seem to have difficulty making the damn holster stay in place when i draw the handgun. more often than not, in a rush the holster comes out with the pistol.
Definitely not a good thing in the one time I need it..

Any ideas/experiences in keeping the damn thing in place? The hook on the paddle barely seems adequate enough to bitee down against the pant lining and belt to keep it in place.

get a belt holster.  Paddles are by design easy to take off, hence, they come off easy.  I've seen it happen with every manufacturer.

I second the belt holster advice. Tell your GF you like it but need something better and more secure for concealed carry.

Does the Galco not have a lip of some sort to hold the waistband? My Fobus I occasionally use has a roung portion of the paddle to grip the lower part of the pants and a lip at the waistline. Try skateboard tape to increase the friction against your pants and see if that's any help.