Thanks Joshua. Quoting a Kenneth Folk post from
this thread that may also prove useful:
"I'd like to clarify about the 'bathing in jhana' instruction you quoted, because understanding it is fundamental to jhana practice. Whether we think of it as active or passive, the job is to let yourself steep in the sensations as they become ever deeper, more solid, more blissful, etc. Whereas you may have entered the jhana by meditating on the breath, a kasina object, a mantra, or any other object, at this point the jhana itself is the object. Everything else is dropped as you allow yourself to be overcome by the pleasant sensations of the jhana. You are a sponge, soaking up the sensations. We are talking about the samatha technique, so there is no effort to investigate or penetrate the object (vipassana). And this "bathing in the jhana" technique is not unique to any particular jhana. This is the way to deepen and solidify ANY jhana, so for those who are getting just a whiff of jhana and would like to go deeper, this is a powerful instruction."