The beginner will try to bore out the inner diameter hole (assuming that they feel the need). If you get the size perfect it may just about do the job but the probability of getting the size right first time is very low. The big problem is that this material is surprisingly dense. A natural vagina maintains firm pressure through a large range. Lets say that the average penis is about 4cm in diameter (don’t go getting out your tape measure, it was a number plucked from the air). Pipe insulation foam will only give you a compression range of about 1.5 cm. In other words there is not very much give. Any design using this material must not solely rely on the foam to form the flesh.
The two variations shown above work ok. They use expansion designs to try to maintain pressure. The bottom one also incorporates bubble wrap to soften the flesh. As I say, they are ok but they look like they should work better than they really do. I was a little disappointed by my experiences building with pipe insulation and would be glad to hear from anyone who has made it work well.
How does it compare to a natural vagina?
Softness – 5/10
Texture – 5/10
Width flexibility and shape – 5/10
Friction – 5/10
Temperature – 6/10
Durability – 6/10
Ease of handing/positioning – 6/10
Authenticity score – 54%
Overall Experience score – 55%