The only thing I remember is a tube appearing under a bed frame in Tribunal. (Make your own conclusions about the implications. http://www.youtube.com/watch?v=AcmrYhDq9ms.)
I dont know about their use as phallic devices, nor as "Butt machines" (Though I am pretty sure the dwemer had considered that prospect in their animunculi...)
But a "http://en.wikipedia.org/wiki/Coherer" is used to pick up and amplify electromagnetic radiation.
http://www.freepatentsonline.com/5963169.html
Some of these devices sound vaguely familiar when held up to the description of a dwemer tube coherer.......
I am not saying that is the purpose it was for, but it would explain their prevelence, and would also help to explain why dwemer animunculi "power off" when they get too far away from their ruins of origin.