I'm trying to create a cybernetic penis that the body would accept as it's own without invasive procedures for the sake of creating a cyborg futanari. Here is my thoughts so far. Create a soft robot that has sensors to mimick pressure, stretch, and vibration sensors of the penis. The clitoris or vagina would then be stimulated by an electrotactile array correlating to the signals. The synthcock may then respond with erection by measuring local blood flow, swelling etc. In theory, this is the same principle as sensory substitution like those blind people who can "see" using a tongue stimulator. Some issues I find are how to mimick the bodies natural afferent pathway ie the strength and duration of graded potentials and the amount of action potentials the penis normally creates on response to stimulus. Hopefully within a few years we will have function robofutanaris with dicks that seem like a part of themselves. Also I guess it could help ftm trannies from killing themselves but that's secondary.