In a double boiler melt the first four ingredients until fully liquid, whisk every so often. Remove from heat and whisk in the essential oil. The brand of the oil will designate how much you put in. Brands like DoTerra & Young are pretty pure so 5 ish drops is plenty. Others, like Now, you need about 20.
Quickly pour the melted oil into the lip balm tubes - seriously, be quick! Yu don't want the oil to set. Allow the oil to set and top up if needed. Cap the containers but leave them to set overnight without touching so they solidify completely.