After practicing Yi Swallows Chi for some time, I became proficient at guiding external chi into my tan tien with my mind.  The technique is so relaxed, and starts from a very familiar intake of chi: breathing.  Additionally, through Yi Swallows Chi, the lower tan tien gets cleared of stagnation, and gradually gains a sort of magnetism, or gravity, of its own: energies are easily drawn into it.  There is a certain kind of feel and ability for guiding chi into the lower tan tien that is produced by the Yi Swallows Chi practice - that I've not experienced from any other practice.  That feel and ability is a pre-requisite for both the solo and dual techniques of this essay: Turtle Breathing.

Essentially, Turtle Breathing is a training method for men to draw qi in through the penis.  The benefits are many, and the intent benign.

In the solo version of Turtle Breathing, you draw the chi from the air in through the urethra (the tip of the penis), and simply guide it with your mind back up the urethra, through the prostate gland, up and around via the vas deferens, and down into the testicles.  (See graphic, below, for anatomical reference.)

The Turtle

This is a very relaxed technique.  It's done in an unaroused state.  The chi is guided by the mind.  Ideally, the practice should be done outside, in pre-sunrise cool air, with the penis directly exposed to the fresh air.  (Local weather, common courtesy, and indecency laws may oblige you to occasionally stray from the ideal.)

This solo technique has a number of benefits, on its own.  

        The chi from the air (the "metal" element) has strong alchemy with the energy of the lower jiao (water), with sexual energy in particular.  You'll find that this exercise strongly clears stagnation from around the urogenital diaphragm, the prostrate gland, the testicles, and the lower abdomen in general.  If you have substantial stagnation to begin with, this technique may cause some initial discomfort as the stagnant chi is dislodged.  This is one of the reasons for the pre-requisite of Yi Swallows Chi: to at least partially clear the way prior to this technique.  If you feel discomfort through this technique, take care to pace yourself compassionately, and to be sensitive to your body's own unique processes and needs.

        In addition to circulation, the chi from the air will tonify the water element as well.

This method brings freshness (from the outside air) and refinement, circulation, and tonification (metal-water alchemy) to the male sexual region.

Turtle Breathing: The Three Lower Pulsings Path

As aroused jing becomes orgasmic, it begins to pulse.  The "three lower pulsings" (not a classic term, made it up just now) that you need to have some integral fluency with are:

    1. tip of the penis

    2. urogenital diaphragm

    3. sacrum

If these three are communicating well, the perineum will take care of itself.  Best way to train for this is to become fluent in sacral pulsing... whatever technique/s work for you, sacrum breathing seems to a good place to start.  Once your sacral pulsing is established, all it really takes is some awareness to include 1&2 (the tip and the urogenital diagraphm).

Once 1,2&3 are pulsing in concert, breathe in from the tip, through the urogenital diaphragm, and into the sacrum.  On the exhale, squeeze the sacrum.  Then perhaps some sacral breathing.  Return to comfortably deep, conscious, natural breathing breathing when you feel the time is right.  Stay integral and steady.

Since the sacral pulsing is the beginning of the spine, spine work is appropriate adjunct, and a later culmination is the ability to let all of the major orbit places pulse integrally.

Turtle Breathing has rather obvious application for dual cultivation: the absorption of female sexual energy by the male during intercourse, with the intent of balance, and within the context of mutual exchange.

The method is essentially the same as when practicing the solo method... Except, of course, this is done in an aroused state, during intercourse.  With practice, you'll find that the sensitivity of the tip of the penis naturally connects with the prostate gland (especially key, that first link of tip-to-prostate)... and then routes back around to the testicles.  All of this also naturally connects with the upper center of the brain, especially the area of the pineal gland.  You'll be surprised that once a sensitivity for these connections is established, that energy can easily be absorbed inward along the path - instead of the more common outward ejaculation.

It's only necessary to absorb small amounts of female essence, all done in a relaxed, gentle manner.  Experience has shown that a rich bliss results, in the prostate, testicles, and whole lower abdomen... very, very, very healing.

In addition to Yi Swallows Chi, and the Solo Cultivation version, "Preparing the body" technique is very helpful preparation for this dual cultivation application.  The "Preparing the body" technique - especially if practiced throughout the day - provides you with good circulation, steady internal focus, and conscious engagement in the dynamics of the lower abdomen... Very helpful for circulating and steadying the energies there during intercourse.

The other obvious aspect of this is giving energy, emanating masculine heat from the penis.  SimonV's HT-USA post #12205 talks about this.  I leave it to your explorations.

NOTE: There are classical phenomena, practices, called "turtle breathing" that are entirely different than this, have nothing to do with breathing through the penis.  I chose the name of this technique on my own, out of playfulness, without connection to the classical technique.