Refusal skills simply means the methods then one can use to say no when one is being pressured into doing a particular thing.
The refusal skill that Leona is forgetting to use in this situation is the use of a firm tone of voice. This can be seen where Leona told Nicole that she doesn't want to break her parents trust when Nicole told her to take some beers. She insisted and used a firm voice that she wasn't going to do what Nicole told her to do.
