Forcing a method to become inline code?

This probably isn't an S/A type of question, but does anyone know how to force the compilation to inline a method? I've got a method that returns if running in debug mode, and if so, overrides a few security checks. However, a hack would just need to override the return value. If this method is called a dozen times, it'd be a whole lot harder to hack if it was inlined for each of the 12 different call locations.