They are implants.
I was at a party in Bristol many years back and one of the guys had what looked like ball bearings inserted under the skin the whole way along his shaft, top and sides.
It was quite a talking point. They had used surgical grade stainless steel and it had taken a while to heel.
The girl in question said she didn't notice any difference during penetration but they kept catching her teeth during oral.
Like the idea of ribbed or studded condoms the actual effect is minimal but this would be a much more expensive and potentially painful way to find out.
