Penis Extension Technology

After noting the subtitle of this Idea, see the first two links. Modern 3D printing techniques have been expanded to include the building of biological structures such as ears, and can even include living cells derived from a particular individual. And the technology is only going to improve with time. SO:

The human penis does not contain any internal hard elements (some mammals have an actual bone in there), but it still has a particular structure of blood vessels and a means of becoming turgid, engorged with blood.

We can use something like an MRI scan to determine the exact internal structure of, say, a 1mm length in the middle of a man's penis. An appropriate 3D printer can print out THAT structure, duplicated along several centimeters, and including cells from the man who had been MRI-scanned.

The living penis can now be cut in the middle of that 1mm section, and separated, and the product of the printer can be inserted into the gap, and connected at both ends to the two parts of the cut penis. After healing, the man now has a longer and likely fully functional organ.