The fifth and six steps in Ananpansati, talk about training ones' self to be sensitive to these feelings, how can a mediator do this and avoid the dangers of getting caught up in them?
If the meditator is trying to "induce" rapture & pleasure, as taught by some meditation teachers, the meditator is already caught up in them.
Buddhism is not the same as the consumer culture, where pleasure is easily obtained.
True rapture & pleasure are a reward for right morality & noble selflessness (non-attachment).
The quality of mind & mindfulness described in the Anapanasati Sutta is as follows:
There is the case where a monk develops mindfulness as a factor for awakening dependent on seclusion, dependent on dispassion, dependent on cessation, resulting in relinquishment. He develops analysis of qualities as a factor for awakening... persistence as a factor for awakening... rapture as a factor for awakening dependent on seclusion, dependent on dispassion, dependent on cessation, resulting in relinquishment... serenity as a factor for awakening... concentration as a factor for awakening... equanimity as a factor for awakening dependent on seclusion, dependent on dispassion, dependent on cessation, resulting in relinquishment.
You simply have to know the presence of the sensation, know it is arising and passing and be equanimous without getting attached to it. Attachment to pleasant sensation gives arise to the unwholesome root of craving. [Pahāna Sutta]
There are two ways this can be interpreted; 1. Attaining the pleasurable feelings and gladness of and by means of subduing the hindrances 2. Pleasuring the mind by reflecting on wholesome and inspiring themes; this also induces wholesome states far removed from unskillful qualities.
Now as it seems to me #2 is included in #1 anyway and will generally come into play in the course of attaining to #1, having attained either one can be said to attain both.
As for the variety of pleasurable feelings to be experienced, the Theravadin Abhidhamma offers a seemingly reasonable system of classifications in the Dhammasanghani.
Therefore i think in practice one can only attain to a variety of pleasure based on sensuality and a range of pleasure not based on sensuality. The latter is attained by staying mindful, ardent & alert and at that time one may become percepient of a variety of pleasurable feelings which may or may not be accompanied by perception of lights & forms.
In another circumstance one may become aware & mindful of ill-will or discontentment being present in the mind, a mind with a hindrance; or that mind is sluggish and lazy. As one is thus obsessed by a hindrance or sluggishness one may address it by developing a rousing theme associated with pleasure like metta, appreciation or recollection of one's virtue or the Triple Gem before withdrawing from that theme in due time and having gladdened the mind.
As i see it, in practice these are the possible ways to gladden the mind. As for the intended meaning of the actual Sutta i think the meaning it is closer to #1 than #2.
A way of not getting caught up in them is as i understand it the reflecting on the mind as it is released and straightening of views supported by reflection.
Here are EBT (early buddhist text) sutta passages that explain how one produces piti/rapture, and the nearly synonymous mudita, pamojja (altruistic joy). http://lucid24.org/sted/7sb/4piti/book/index.html
Ajahn Lee's book "Keeping the breath in mind" is a classic, this is my personal favorite book on breath meditation.
His student, the famous B. Thanissaro also has an excellent book on breath meditation, "with each and every breath", I'd say the most complete and authentic EBT guide to breath meditation in existence.
(Just google those authors and titles for the various free ebook formats pdf, epub, etc)
Now if you're really serious about your spiritual practice, and you want to experience 2nd jhana and higher, with a very powerful piti (rapture) and pleasure (sukha), you're going to need to keep 8 precepts, celibacy, lots of noble silence, and at least 4 hours a day of quiet meditation (sitting or standing). That will charge up your jhana battery. Otherwise, living an ordinary worldly lifestyle, people have weak batteries and are constantly draining their batteries through sex, sensual pleasures, talking too much, and the pitisukha in meditation may be too weak to be felt as anything unusual.
That's the secret sauce that most teachers don't know or don't teach. Since monastics have to keep 8 precepts anyway, then that's just normal for them and no need to ever mention. But for lay people, you're never going to experience strong forceful piti sukha unless you nurture the battery and charge it up.
If you want to experience rapture and pleasure you must work yourself up to attain first jhana.
"There is the case where a monk — quite withdrawn from sensuality, withdrawn from unskillful qualities — enters and remains in the first jhana: rapture and pleasure born from withdrawal, accompanied by directed thought and evaluation. He permeates and pervades, suffuses and fills this very body with the rapture and pleasure born from withdrawal. There is nothing of his entire body unpervaded by rapture and pleasure born from withdrawal.
"Just as if a skilled bathman or bathman's apprentice would pour bath powder into a brass basin and knead it together, sprinkling it again and again with water, so that his ball of bath powder — saturated, moisture-laden, permeated within and without — would nevertheless not drip; even so, the monk permeates, suffuses and fills this very body with the rapture and pleasure born of withdrawal. There is nothing of his entire body unpervaded by rapture and pleasure born from withdrawal...
The practice of metta for all human beings brought me to this experinece [although temporary]. I felt withdrawn from my surroundings with a sense of compassion for human beings. More concentrated, compared to my materialistic way of life. I felf pleasure and rapture in my [almost] entire body.
This Metta actually changes your POV in life. You can actually become a spiritual being, a real humanitarian in the true sense of the term.
The feeligs of rapture and pleasure become present in your heart as you develop love and your heart becomes cleansed from materialistic dirt. This is experiental statement and it cannot be understood by reading; you must gain experience. At the same time, as stated in the quote above, you become withdrawn from worldly affairs. So please do practice Metta for your own beneft.
If you get caught up in the feeligs of rapture and pleasure, you will stop your practice. This is expected in the beginning, when you experience apture and pleasure for the first time and start making new ideas of self. My advice is to steadily continue your practice and become more experienced and intelligent.