[header] How to create air freshener inside a toilet paper roll [title] Select an oil scent that is pleasing and not overpowering. [step] Since the bathroom is (most likely) one of the smaller rooms in your home, you want an oil scent that is calming and soothing. Avoid overly pungent or powerful oils, which may still mask any odor but may be unpleasant to some. 
[title] Consider choosing more than one oil scent. [step] You don't have to be limited to only one essential oil.