The Deep Dydoe piercing (also known as a Zephyr piercing) is just that — a deep dydoe piercing. The top hole is in the standard position in the valley of the coronal ridge. The exit point is next to the urethral opening, with the barbell traveling just under the surface of the glans, theoretically stimulating the nerve endings in a way similar the ampallang functions.
This piercing is anatomy-dependent to some extent. Not only does it require someone with a reasonably prominent coronal ridge, but the glans shape should allow for a good exit to eliminate migration problems. Finally, it is important that jewelry sizing take into account any size changes between flaccid and erect states.