There's no one right way to do everything. It just depends on your relationship and what you guys are comfortable with. Mainly, what YOU (and her as well to an extent) want.

Do you want her to ask you more if you need anything? Or if there is anything she could do for you? And if you want her to be ready for sex, play...etc all the time, then just tell her that you expect her to always be ready to see to your needs. If not and you prefer to do a little of both...that is fine as well. Maybe instead of telling her to be 'ready' 24/7...you could pick a day in particular...start out slow.

Anyone that tries to tell you "this is wrong...there is only one right way to do this" blah blah blah... Yeah...they are blowing smoke outta their ass just to see if they can make smoke rings! Don't listen to em! Just focus on doing what is comfortable for you and her in your relationship.