Realistc 3D penis, rigged and with simulated, accurate foreskin sliding. I made this model and rig from scratch, but the rig is based on the method used in IceDev's Male Ultimate.

UPDATE: USE THE NEW 1.1 VERSION The old version had a missing armature modifier that was important for the rig, now it's fixed

Note that this model makes use of high-resolution displacement maps in addition to your standard normal maps, so it gets heavy with the Subdivision Surface modifier enabled in the viewport.

It's made with Cycles in mind, but it should work fine with Eevee, with some tewaks to the shader. You'll have to move the displacement texture to a modifier for it to work with Eevee though.

TO CUSTOMIZE THE OVERALL SHAPE OF THE MODEL: I've included a low poly cage that you can use with the Mesh Deform modifier. Bind it to the mesh at the subdivision level you are planning to render in; otherwise it won't work. Leave the first subdivision modifier at the value of 2, change the second one if you want higher/lower resolution.

You can find me at https://twitter.com/ThineCrawler